×

The period of the Bell numbers modulo a prime. (English) Zbl 1216.11028

Summary: We discuss the numbers in the title, and in particular whether the minimum period of the Bell numbers modulo a prime \( p\) can be a proper divisor of \( N_p = (p^p-1)/(p-1)\). It is known that the period always divides \( N_p\). The period is shown to equal \( N_p\) for most primes \( p\) below 180. The investigation leads to interesting new results about the possible prime factors of \( N_p\). For example, we show that if \( p\) is an odd positive integer and \( m\) is a positive integer and \( q=4m^2 p+1\) is prime, then \( q\) divides \( p^{m^2p}-1\). Then we explain how this theorem influences the probability that \( q\) divides \( N_p\).

MSC:

11B73 Bell and Stirling numbers
11A05 Multiplicative structure; Euclidean algorithm; greatest common divisors
11A07 Congruences; primitive roots; residue systems
11A51 Factorization; primality
Full Text: DOI

References:

[1] Paul T. Bateman and Roger A. Horn, A heuristic asymptotic formula concerning the distribution of prime numbers, Math. Comp. 16 (1962), 363 – 367. · Zbl 0105.03302
[2] C. E. Bickmore. Problem 13058. Math. Quest. Educ. Times, 65:78, 1896.
[3] Mireille Car, Luis H. Gallardo, Olivier Rahavandrainy, and Leonid N. Vaserstein, About the period of Bell numbers modulo a prime, Bull. Korean Math. Soc. 45 (2008), no. 1, 143 – 155. · Zbl 1195.11034 · doi:10.4134/BKMS.2008.45.1.143
[4] L. E. Dickson. History of the Theory of Numbers, volume 1: Divisibility and Primality. Chelsea Publishing Company, New York, New York, 1971.
[5] Jack Levine and R. E. Dalton, Minimum periods, modulo \?, of first-order Bell exponential integers., Math. Comp. 16 (1962), 416 – 423. · Zbl 0113.03402
[6] W. F. Lunnon, P. A. B. Pleasants, and N. M. Stephens, Arithmetic properties of Bell numbers to a composite modulus. I, Acta Arith. 35 (1979), no. 1, 1 – 16. · Zbl 0408.10006
[7] J. Sabia and S. Tesauri. The least prime in certain arithmetic progressions. Amer. Math. Monthly, 116:641-643, 2009. · Zbl 1229.11012
[8] J. Touchard. Propriétés arithmétiques de certains nombres recurrents. Ann. Soc. Sci. Bruxelles, 53A:21-31, 1933.
[9] Samuel S. Wagstaff Jr., Divisors of Mersenne numbers, Math. Comp. 40 (1983), no. 161, 385 – 397. · Zbl 0507.10005
[10] Samuel S. Wagstaff Jr., Aurifeuillian factorizations and the period of the Bell numbers modulo a prime, Math. Comp. 65 (1996), no. 213, 383 – 391. · Zbl 0852.11008
[11] G. T. Williams, Numbers generated by the function \?^{\?^{\?}-1}, Amer. Math. Monthly 52 (1945), 323 – 327. · Zbl 0060.08416 · doi:10.2307/2305292
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.