A071931 Non-Størmer numbers whose largest prime factor is a Størmer number.

8, 30, 32, 38, 46, 50, 55, 57, 75, 76, 99, 100, 111, 122, 128, 132, 133, 142, 174, 177, 183, 185, 200, 203, 212, 213, 228, 237, 242, 253, 254, 265, 266, 268, 274, 278, 302, 305, 319, 322, 327, 334, 342, 348, 360, 377, 380, 381, 394, 395, 411, 413, 418, 437

Offset

1,1

Links

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

Prog

(Haskell)
a071931 n = a071931_list !! (n-1)
a071931_list = filter f a002312_list where
   f x = 2 * gpf <= a006530 (gpf ^ 2 + 1) where gpf = a006530 x
-- Reinhard Zumkeller, Jun 12 2015
(Python)
from sympy import factorint
def stormer(n): return max(factorint(n*n + 1)) >= 2*n
def ok(n): return not stormer(n) and stormer(max(factorint(n)))
print(list(filter(ok, range(1, 438)))) # Michael S. Branicky, Aug 30 2021

Crossrefs

Cf. A005528, A002312.

Cf. A006530.

Sequence in context: A189946 A239855 A239029 * A333657 A074670 A092277

Adjacent sequences: A071928 A071929 A071930 * A071932 A071933 A071934

Keyword

nonn

Author

Jason Earls, Jun 14 2002

Status

approved