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Numbers having no divisor of the form 8*k + 7.
8

%I #11 Apr 06 2021 11:03:45

%S 1,2,3,4,5,6,8,9,10,11,12,13,16,17,18,19,20,22,24,25,26,27,29,32,33,

%T 34,36,37,38,40,41,43,44,48,50,51,52,53,54,57,58,59,61,64,65,66,67,68,

%U 72,73,74,76,80,81,82,83,85,86,88,89,96,97,99,100,101,102

%N Numbers having no divisor of the form 8*k + 7.

%C Numbers not divisible by at least one of 7, 15, 23, ...

%H Jianing Song, <a href="/A343110/b343110.txt">Table of n, a(n) for n = 1..10000</a>

%e 9 is a term since it has no divisor congruent to 7 modulo 8.

%o (PARI) res(n,a,b) = sumdiv(n, d, (d%a) == b)

%o isA343110(n) = (res(n,8,7) == 0)

%Y Numbers having m divisors of the form 8*k + i: A343107 (m=1, i=1), A343108 (m=0, i=3), A343109 (m=0, i=5), this sequence (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 A188172.

%K nonn,easy

%O 1,2

%A _Jianing Song_, Apr 05 2021