cp's OEIS Frontend

A373590 Numbers whose number of prime factors (with multiplicity) is a multiple of 3, and all of them are of the type 3m+1 (in A002476).

%I A373590 #10 Jun 10 2024 23:34:59
%S A373590 1,343,637,931,1183,1519,1729,1813,2107,2197,2527,2821,2989,3211,3283,
%T A373590 3367,3577,3871,3913,4123,4693,4753,4921,5047,5239,5341,5551,5719,
%U A373590 6097,6223,6253,6643,6727,6811,6859,7189,7267,7399,7657,7693,7987,8029,8113,8827,8869,8911,9139,9331,9373,9457,9583,9709,9751,9919
%N A373590 Numbers whose number of prime factors (with multiplicity) is a multiple of 3, and all of them are of the type 3m+1 (in A002476).
%C A373590 A multiplicative semigroup: if m and n are in the sequence, then so is m*n.
%H A373590 Antti Karttunen, <a href="/A373590/b373590.txt">Table of n, a(n) for n = 1..20000</a>
%o A373590 (PARI) isA373590(n) = if(bigomega(n)%3, 0, my(f = factor(n)); for(i = 1, #f~, if((f[i, 1]%3) != 1, return(0))); (1));
%Y A373590 Intersection of A004611 and A145784.
%Y A373590 Subsequence of A373597 (see also A373589).
%Y A373590 Cf. A001222, A002476.
%K A373590 nonn
%O A373590 1,2
%A A373590 _Antti Karttunen_, Jun 10 2024