A152986 Sum of proper divisors minus the number of proper divisors of pentagonal number A000326(n).

0, 0, 11, 11, 10, 18, 67, 71, 60, 32, 187, 351, 30, 46, 519, 337, 128, 220, 577, 483, 366, 286, 507, 1153, 248, 336, 2489, 847, 70, 818, 871, 2181, 1108, 116, 2861, 2275, 694, 130, 2763, 3645, 100, 2352, 2823, 1863, 2278, 158, 3607, 6617, 636, 920, 6181, 4019

Offset

1,3

Links

B. D. Swan, Table of n, a(n) for n = 1..10000

Formula

a(n)=A001065(A000326(n))-A032741(A000326(n)) = A152770(A000326(n)).

Maple

A000326 := proc(n) n*(3*n-1)/2 ; end: A000203 := proc(n) numtheory[sigma](n) ; end: A000005 := proc(n) numtheory[tau](n) ; end: A152770 := proc(n) A000203(n)-A000005(n)-n+1 ; end: A152986 := proc(n) A152770(A000326(n)) ; end: for n from 1 to 80 do printf("%a, ", A152986(n)) ; od: # R. J. Mathar, Jan 03 2009

Mathematica

DivisorSigma[1, #]-#-DivisorSigma[0, #]+1&/@PolygonalNumber[5, Range[60]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 02 2021 *)

Crossrefs

Cf. A000005, A000203, A000326, A001065, A032741, A152770.

Sequence in context: A321108 A126610 A087380 * A252838 A366717 A212541

Adjacent sequences: A152983 A152984 A152985 * A152987 A152988 A152989

Keyword

easy,nonn,look

Author

Omar E. Pol, Dec 22 2008

Extensions

Extended by R. J. Mathar, Jan 03 2009

Status

approved