A388979 a(n) = A326127(n) * A389078(n).

0, 0, 0, 16, 0, 0, 0, 120, 72, 0, 0, 520, 0, 0, 0, 1120, 0, 1368, 0, 952, 0, 0, 0, 3600, 240, 0, 1200, 1848, 0, 0, 0, 6960, 0, 0, 0, 12096, 0, 0, 0, 6720, 0, 0, 0, 3016, 4704, 0, 0, 29200, 840, 5904, 0, 4488, 0, 21600, 0, 13200, 0, 0, 0, 26040, 0, 0, 8976, 45136, 0, 0, 0, 6232, 0, 0, 0, 81312, 0, 0, 11040, 8280

Offset

1,4

Links

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

Index entries for sequences computed from indices in prime factorization.

Index entries for sequences related to sigma(n).

Formula

a(n) = A341529(n) - A007913(n)*A003961(n) + A191002(A007913(n)) - A191002(n) - A000203(n)*A003961(A007913(n)) + n*A003961(A007913(n)).

a(n) >= A388978(n).

Prog

(PARI)
A003961(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
A388979(n) = ((sigma(n)-core(n)-n)*(A003961(n)-A003961(core(n))));

Crossrefs

Cf. A000203, A003961, A003973, A007913, A191002, A388979.

Cf. also A341528 & A341529, and A388976 & A388977.

Sequence in context: A023919 A306282 A336432 * A169767 A225611 A173293

Adjacent sequences: A388976 A388977 A388978 * A388980 A388981 A388982

Keyword

nonn

Author

Antti Karttunen, Sep 23 2025

Status

approved