The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A359796 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A359796

a(n) = Sum_{d|n} (2*d)^(d-1).
(history; published version)

#12 by Joerg Arndt at Mon Aug 14 02:00:29 EDT 2023

STATUS

reviewed

approved

#11 by Michel Marcus at Mon Aug 14 01:34:42 EDT 2023

STATUS

proposed

reviewed

#10 by Amiram Eldar at Mon Aug 14 00:18:19 EDT 2023

STATUS

editing

proposed

#9 by Amiram Eldar at Mon Aug 14 00:13:27 EDT 2023

MATHEMATICA

a[n_] := DivisorSum[n, (2*#)^(# - 1) &]; Array[a, 20] (* Amiram Eldar, Aug 14 2023 *)

STATUS

approved

editing

#8 by Michael De Vlieger at Fri Jan 13 09:18:08 EST 2023

STATUS

proposed

approved

#7 by Seiichi Manyama at Fri Jan 13 09:03:17 EST 2023

STATUS

editing

proposed

#6 by Seiichi Manyama at Fri Jan 13 09:00:34 EST 2023

CROSSREFS

Cf. A262843, A359731.

#5 by Seiichi Manyama at Fri Jan 13 08:59:44 EST 2023

FORMULA

G.f.: Sum_{k>0} (2 * k)^(k-1) * x^k / (1 - x^k).

#4 by Seiichi Manyama at Fri Jan 13 08:59:00 EST 2023

PROG

(PARI) my(N=20, x='x+O('x^N)); Vec(sum(k=1, N, (2*k)^(k-1)*x^k/(1-x^k)))

KEYWORD

nonn,changed,easy

#3 by Seiichi Manyama at Fri Jan 13 08:57:14 EST 2023

PROG

(PARI) a(n) = sumdiv(n, d, (2*d)^(d-1));