OFFSET
1,3
LINKS
Hugo Pfoertner, Table of n, a(n) for n = 1..116
Andreas Enge, William Hart, Fredrik Johansson, Short addition sequences for theta functions, arXiv:1608.06810 [math.NT], 2016-2018. See Table 5.
FORMULA
MATHEMATICA
a290731[n_] := Product[{p, e} = pe; If[p==2, 2^(e-1), 1 + Quotient[p^(e+1), (2p + 2)]], {pe, FactorInteger[n]}];
Reap[For[r = 2; k = 1, k <= 200000, k++, v = a290731[k]; t = v/k; If[t < r, r = t; Sow[v]]]][[2, 1]] (* Jean-François Alcover, Sep 13 2018, from PARI *)
PROG
(PARI) a290731(n)={my(f=factor(n)); prod(i=1, #f~, my([p, e]=f[i, ]); if(p==2, 2^(e-1), 1+p^(e+1)\(2*p+2)))} \\ from Andrew Howroyd
r=2; for(k=1, 200000, v=a290731(k); t=v/k; if(t<r, r=t; print1(v, ", "))) \\ Hugo Pfoertner, Aug 23 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Aug 10 2017
EXTENSIONS
More terms from Hugo Pfoertner, Aug 22 2018
Initial term added by Hugo Pfoertner, Aug 23 2018
STATUS
approved