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A157020 a(n) = Sum_{d|n} d*binomial(n/d+d-2,d-1).

%I A157020 #20 Sep 03 2019 15:14:53
%S A157020 1,3,4,9,6,22,8,33,28,46,12,131,14,78,136,177,18,307,20,456,302,166,
%T A157020 24,1149,376,222,568,1177,30,2387,32,1761,958,358,2556,5224,38,438,
%U A157020 1496,7851,42,8317,44,4863,9136,622,48,20169,6518,11451,3112,8516,54,23734
%N A157020 a(n) = Sum_{d|n} d*binomial(n/d+d-2,d-1).
%C A157020 Equals row sums of triangle A157497. [_Gary W. Adamson_ & _Mats Granvik_, Mar 01 2009]
%H A157020 Seiichi Manyama, <a href="/A157020/b157020.txt">Table of n, a(n) for n = 1..10000</a>
%F A157020 G.f.: Sum_{n>=1} n*x^n/(1-x^n)^n.
%p A157020 add( d*binomial(n/d+d-2,d-1),d=numtheory[divisors](n) ) ;
%o A157020 (PARI) N=66; x='x+O('x^N); Vec(sum(k=1, N, k*x^k/(1-x^k)^k)) \\ _Seiichi Manyama_, Sep 03 2019
%Y A157020 Cf. A081543, A132065, A156833 (Mobius transform), A324158, A324159.
%K A157020 easy,nonn,look
%O A157020 1,2
%A A157020 _R. J. Mathar_, Feb 21 2009