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).

1, 343, 637, 931, 1183, 1519, 1729, 1813, 2107, 2197, 2527, 2821, 2989, 3211, 3283, 3367, 3577, 3871, 3913, 4123, 4693, 4753, 4921, 5047, 5239, 5341, 5551, 5719, 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

Offset: 1

Author

Antti Karttunen, Jun 10 2024

Keywords

• nonn

Comments

A multiplicative semigroup: if m and n are in the sequence, then so is m*n.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..20000

Crossrefs

Intersection of A004611 and A145784.

Subsequence of A373597 (see also A373589).

Cf. A001222, A002476.

Programs

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));