A221265 - OEIS

A221265

Numbers having more distinct prime factors of form 4*k+1 than of 4*k+3.

5, 10, 13, 17, 20, 25, 26, 29, 34, 37, 40, 41, 50, 52, 53, 58, 61, 65, 68, 73, 74, 80, 82, 85, 89, 97, 100, 101, 104, 106, 109, 113, 116, 122, 125, 130, 136, 137, 145, 146, 148, 149, 157, 160, 164, 169, 170, 173, 178, 181, 185, 193, 194, 195, 197, 200, 202

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

A005089(a(n)) > A005091(a(n)); A005094(a(n)) > 0.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

MATHEMATICA

mdpf1Q[n_]:=Module[{f=Transpose[FactorInteger[n]][[1]]}, Count[f, _?(Mod[ #, 4] == 1&)]>Count[f, _?(Mod[#, 4]==3&)]]; Select[Range[2, 250], mdpf1Q] (* Harvey P. Dale, Mar 03 2016 *)

PROG

(Haskell)

a221265 n = a221265_list !! (n-1)

a221265_list = filter ((> 0) . a005094) [1..]

CROSSREFS

Cf. A078613, A221264.

Cf. A005089, A005091, A005094.

Sequence in context: A004431 A025302 A268379 * A055096 A313386 A267969

Adjacent sequences: A221262 A221263 A221264 * A221266 A221267 A221268

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jan 07 2013

STATUS

approved