The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A034715 Dirichlet convolution of triangular numbers with themselves. 4
 1, 6, 12, 29, 30, 78, 56, 132, 126, 200, 132, 402, 182, 378, 420, 588, 306, 864, 380, 1050, 798, 902, 552, 1920, 875, 1248, 1296, 2002, 870, 2940, 992, 2592, 1914, 2108, 2100, 4635, 1406, 2622, 2652, 5080, 1722, 5628, 1892, 4818, 4860, 3818, 2256, 8856 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Bruno Berselli, Table of n, a(n) for n = 1..1000 FORMULA G.f.: Sum_{k>=1} (k*(k + 1)/2)*x^k/(1 - x^k)^3. - Ilya Gutkovskiy, Oct 24 2018 From Vaclav Kotesovec, Feb 05 2019: (Start) Dirichlet g.f.: ((zeta(s-1) + zeta(s-2))/2)^2. Sum_{k=1..n} a(k) ~ n^3*(log(n)/12 + (6*gamma - 1 + Pi^2)/36), where gamma is the Euler-Mascheroni constant A001620. (End) MATHEMATICA Table[n/4*Sum[(n+d)*(d+1)/d, {d, Divisors[n]}], {n, 1, 50}] (* Vaclav Kotesovec, Feb 05 2019 *) PROG (Magma) A000217:=func; [&+[A000217(d)*A000217(n div d): d in Divisors(n)]: n in [1..50]]; // Bruno Berselli, Feb 11 2014 CROSSREFS Cf. A000217. Sequence in context: A323652 A223346 A109510 * A294730 A079390 A124679 Adjacent sequences: A034712 A034713 A034714 * A034716 A034717 A034718 KEYWORD nonn AUTHOR STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified March 29 11:44 EDT 2023. Contains 361599 sequences. (Running on oeis4.)