A391864 Numbers k such that A003415(k) == A276085(k) (mod 2310), where A003415 is the arithmetic derivative and A276085 is the primorial base log-function.

1, 2, 10, 15, 28, 161, 2189, 2308, 4618, 5005, 6924, 6927, 7917, 9684, 11024, 11540, 11548, 11555, 16331, 18478, 20772, 20788, 21147, 23098, 23105, 24660, 27717, 27718, 29861, 30028, 31065, 32501, 33596, 34644, 34647, 34814, 37404, 38981, 39268, 41577, 41578, 42948, 46198, 46205, 47306, 49855, 50818, 52556, 52601

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..23520; terms less than 2^25

Formula

{k such that A391946(k) == A003415(k) (mod 2310)}.

Prog

(PARI) is_A391864(n) = { my(f=factor(n), pr=1, q=1, ad=n*sum(i=1, #f~, f[i, 2]/f[i, 1]), s = (-ad)%2310); for(k=1, #f~, if(f[k, 1]>11, return(!(s%2310))); forprime(p = nextprime(1+q), f[k, 1]-1, pr *= p; q = p); s += f[k, 2]*pr); (!(s%2310)); };

Crossrefs

Cf. A003415, A276085, A391946.

Subsequence of A392593.

Subsequences: A369650, A391947 (terms k such that k+1 is also a term).

Cf. also A391865, A392598.

Sequence in context: A134861 A063610 A392601 * A391865 A369650 A392868

Adjacent sequences: A391861 A391862 A391863 * A391865 A391866 A391867

Keyword

nonn

Author

Antti Karttunen, Jan 16 2026

Status

approved