A391866 Nonsquarefree numbers k that are not divisible by p^p for any prime p, and for which A276085(k) is a multiple of A003557(k), where A276085 is the primorial base log-function.

150, 294, 578, 1050, 1083, 1650, 1694, 1950, 2535, 2550, 2625, 2850, 3234, 3450, 3630, 3822, 4350, 4650, 4998, 5145, 5550, 5586, 6150, 6375, 6450, 6762, 7050, 7942, 7950, 8526, 8850, 8918, 9114, 9150, 9295, 10050, 10571, 10650, 10878, 10950, 10982, 11550, 11625, 11850, 12054, 12450, 12642, 13294, 13350, 13650, 13818

Offset

1,1

Links

Antti Karttunen, Table of n, a(n) for n = 1..10000

Formula

{k such that A008966(k) = 0, A359550(k) = 1 and A003557(k) | A276085(k)}.

Prog

(PARI)
A003557(n) = (n/factorback(factor(n)[, 1]));
A276085(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*prod(i=1, primepi(f[k, 1]-1), prime(i))); };
A359550(n) = { my(pp); forprime(p=2, , pp = p^p; if(!(n%pp), return(0)); if(pp > n, return(1))); };
is_A391866(n) = (!issquarefree(n) && A359550(n) && !(A276085(n)%A003557(n)));

Crossrefs

Cf. A003557, A008966, A276085, A359550.

Subsequence of A371083.

Cf. A392592 (subsequence).

Cf. also A371086.

Sequence in context: A184075 A207044 A292705 * A392592 A335145 A063829

Adjacent sequences: A391863 A391864 A391865 * A391867 A391868 A391869

Keyword

nonn

Author

Antti Karttunen, Jan 16 2026

Status

approved