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 A280556 a(n) = Sum_{k=1..n} k^2 * (k+1)!. 1
 0, 2, 26, 242, 2162, 20162, 201602, 2177282, 25401602, 319334402, 4311014402, 62270208002, 958961203202, 15692092416002, 271996268544002, 4979623993344002, 96035605585920002, 1946321606541312002, 41359334139002880002, 919636959090769920002, 21356013827774545920002 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Partial sums of 2*A055533. LINKS Seiichi Manyama, Table of n, a(n) for n = 0..446 Mathematical Reflections, Problem J256, Issue 1, 2013, p 4. Mathematical Reflections, Solution to Problem J256, Issue 2, 2013, p 4. FORMULA a(n) =  (n - 1)*(n + 2)! + 2 (see 2nd Mathematical Reflections link). Cf. A052520. E.g.f.: 2*exp(x) - 2*(1 - 4*x)/(1 - x)^4. - Ilya Gutkovskiy, Jan 05 2017 MAPLE A280556:=n->add(k^2*(k+1)!, k=1..n): seq(A280556(n), n=0..30); # Wesley Ivan Hurt, Jan 05 2017 MATHEMATICA Table[Sum[k^2 (k+1)!, {k, n}], {n, 0, 20}] (* Harvey P. Dale, Jun 05 2017 *) PROG (PARI) a(n) = sum(k=1, n, k^2*(k+1)!) CROSSREFS Cf. A052520, A055533. Sequence in context: A178884 A211319 A121768 * A198960 A289263 A296600 Adjacent sequences:  A280553 A280554 A280555 * A280557 A280558 A280559 KEYWORD nonn AUTHOR Michel Marcus, Jan 05 2017 STATUS approved

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Last modified September 22 05:47 EDT 2019. Contains 327287 sequences. (Running on oeis4.)