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A175705 Convolution square of A001157 (the sum of squared divisors). 0
1, 10, 45, 142, 362, 780, 1561, 2762, 4808, 7570, 12034, 17482, 26072, 35884, 50909, 67012, 92111, 116950, 155720, 193564, 250914, 304244, 389286, 461654, 578952, 680944, 839304, 970094, 1188924, 1354164, 1637145, 1858344, 2215866, 2485068 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..34.

FORMULA

a(n) = Sum_{k=1..n} A001157(n)* A001157(n+1-k).

G.f.: (1/x)*(Sum_{k>=1} k^2*x^k/(1 - x^k))^2. - Ilya Gutkovskiy, Jan 01 2017

MAPLE

with(numtheory): T:=array(1..200):for p from 1 to 200 do: liste:=divisors(p) :s2:=sum(liste[i]^2, i=1..nops(liste)):T[p] :=s2 :od : for n from 1 to 100 do: printf(`%d, `, sum (T[k]*T[n+1-k], k=1..n)):od:

CROSSREFS

Cf. A001157.

Sequence in context: A037270 A027800 A005714 * A143671 A221532 A241432

Adjacent sequences:  A175702 A175703 A175704 * A175706 A175707 A175708

KEYWORD

nonn

AUTHOR

Michel Lagneau, Aug 10 2010

EXTENSIONS

Definition slightly rephrased by R. J. Mathar, Aug 19 2010

STATUS

approved

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Last modified March 22 04:32 EDT 2019. Contains 321406 sequences. (Running on oeis4.)