A071931 - OEIS

%I #15 Aug 30 2021 10:54:02

%S 8,30,32,38,46,50,55,57,75,76,99,100,111,122,128,132,133,142,174,177,

%T 183,185,200,203,212,213,228,237,242,253,254,265,266,268,274,278,302,

%U 305,319,322,327,334,342,348,360,377,380,381,394,395,411,413,418,437

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

%H Reinhard Zumkeller, <a href="/A071931/b071931.txt">Table of n, a(n) for n = 1..10000</a>

%o (Haskell)

%o a071931 n = a071931_list !! (n-1)

%o a071931_list = filter f a002312_list where

%o    f x = 2 * gpf <= a006530 (gpf ^ 2 + 1) where gpf = a006530 x

%o -- _Reinhard Zumkeller_, Jun 12 2015

%o (Python)

%o from sympy import factorint

%o def stormer(n): return max(factorint(n*n + 1)) >= 2*n

%o def ok(n): return not stormer(n) and stormer(max(factorint(n)))

%o print(list(filter(ok, range(1, 438)))) # _Michael S. Branicky_, Aug 30 2021

%Y Cf. A005528, A002312.

%Y Cf. A006530.

%K nonn

%O 1,1

%A _Jason Earls_, Jun 14 2002