A229342 a(n) = sigma(n'), the sum of divisors of the arithmetic derivative of n.

1, 1, 7, 1, 6, 1, 28, 12, 8, 1, 31, 1, 13, 15, 63, 1, 32, 1, 60, 18, 14, 1, 84, 18, 24, 40, 63, 1, 32, 1, 186, 24, 20, 28, 168, 1, 32, 31, 126, 1, 42, 1, 124, 56, 31, 1, 248, 24, 78, 42, 120, 1, 121, 31, 168, 36, 32, 1, 168, 1, 48, 72, 508, 39, 62, 1, 195, 42

Offset

2,3

Comments

a(1) is undefined.

Links

Antti Karttunen, Table of n, a(n) for n = 2..20000

Formula

a(n) = A000203(A003415(n)).

Example

For n=4, sigma(n') = sigma(4') = sigma(4) = 7.
For n=7, sigma(n') = sigma(7') = sigma(1) = 1.

Prog

(PARI) rd(n) = {local(fac); if(n<1, 0, fac=factor(n); sum(i=1, matsize(fac)[1], n*fac[i, 2]/fac[i, 1]; )); } \\ from A003415
a(n) = sigma(rd(n)); \\ Michel Marcus, Sep 24 2013

Crossrefs

Cf. A000203, A003415.

Cf. also A229340, A229341, A229343, A229344.

Sequence in context: A154932 A026497 A010146 * A374775 A176438 A092615

Adjacent sequences: A229339 A229340 A229341 * A229343 A229344 A229345

Keyword

nonn

Author

Luca Brigada Villa, Sep 24 2013

Status

approved