Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #12 Apr 06 2021 11:03:48
%S 1,2,3,4,6,7,8,9,11,12,14,16,17,18,19,22,23,24,27,28,31,32,33,34,36,
%T 38,41,43,44,46,47,48,49,51,54,56,57,59,62,64,66,67,68,71,72,73,76,79,
%U 81,82,83,86,88,89,92,94,96,97,98,99,102,103,107,108,112,113
%N Numbers having no divisor of the form 8*k + 5.
%C Numbers not divisible by at least one of 5, 13, 21, ...
%H Jianing Song, <a href="/A343109/b343109.txt">Table of n, a(n) for n = 1..10000</a>
%e 9 is a term since it has no divisor congruent to 5 modulo 8.
%o (PARI) res(n,a,b) = sumdiv(n, d, (d%a) == b)
%o isA343109(n) = (res(n,8,5) == 0)
%Y Numbers having m divisors of the form 8*k + i: A343107 (m=1, i=1), A343108 (m=0, i=3), this sequence (m=0, i=5), A343110 (m=0, i=7), A343111 (m=2, i=1), A343112 (m=1, i=3), A343113 (m=1, i=5), A141164 (m=1, i=7).
%Y Indices of 0 in A188171.
%K nonn,easy
%O 1,2
%A _Jianing Song_, Apr 05 2021