A164533 a(n) = sigma(sigma(n))*sigma(n).

1, 12, 28, 56, 72, 336, 120, 360, 182, 702, 336, 1568, 336, 1440, 1440, 992, 702, 2184, 840, 4032, 2016, 3276, 1440, 10080, 992, 4032, 3600, 6720, 2160, 14040, 2016, 6552, 5952, 6480, 5952, 10192, 2280, 10080, 6720, 21060, 4032, 24192, 3696, 18816, 13104

Offset

1,2

Links

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

Index entries for sequences related to sigma(n)

Formula

a(n) = A051027(n) * A000203(n).

Example

a(1) = 1*1 = 1; a(2) = 4*3 = 12.

Maple

A000203 := proc(n) numtheory[sigma](n) ; end:
A051027 := proc(n) A000203(A000203(n)) ; end:
A164533 := proc(n) A051027(n)*A000203(n) ; end: seq(A164533(n), n=1..80) ; # R. J. Mathar, Aug 19 2009

Mathematica

Table[DivisorSigma[1, DivisorSigma[1, n]]*DivisorSigma[1, n], {n, 1, 50}] (* G. C. Greubel, Mar 16 2019 *)

Prog

(PARI) A164533(n) = (sigma(sigma(n))*sigma(n)); \\ Antti Karttunen, Nov 17 2017
(PARI) a(n) = my(s = sigma(n)); s * sigma(s) \\ David A. Corneth, Nov 17 2017
(Magma) [DivisorSigma(1, DivisorSigma(1, n))*DivisorSigma(1, n): n in [1..50]]; // G. C. Greubel, Mar 16 2019
(Sage) [sigma(sigma(n))*sigma(n) for n in (1..50)] # G. C. Greubel, Mar 16 2019

Crossrefs

Cf. A000203, A051027.

Sequence in context: A183053 A126195 A248547 * A034319 A097427 A039366

Adjacent sequences: A164530 A164531 A164532 * A164534 A164535 A164536

Keyword

nonn

Author

Juri-Stepan Gerasimov, Aug 15 2009

Extensions

Terms checked by R. J. Mathar, Aug 19 2009

Status

approved