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Numbers having no divisor of the form 8*k + 5.
8

%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