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A094323
a(n) = n*(n+1)*(2n+1)*(3n+1)*(4n+1)/30.
2
0, 4, 63, 364, 1326, 3696, 8645, 17864, 33660, 59052, 97867, 154836, 235690, 347256, 497553, 695888, 952952, 1280916, 1693527, 2206204, 2836134, 3602368, 4525917, 5629848, 6939380, 8481980, 10287459, 12388068, 14818594, 17616456, 20821801, 24477600, 28629744
OFFSET
0,2
FORMULA
From Amiram Eldar, Mar 08 2022: (Start)
Sum_{n>=1} 1/a(n) = 300 + (135*sqrt(3)/2 - 160)*Pi - 1200*log(2) + 1215*log(3)/2.
Sum_{n>=1} (-1)^(n+1)/a(n) = (60 + 160*sqrt(2) - 135*sqrt(3))*Pi + (160*sqrt(2) - 380)*log(2) - 320*sqrt(2)*log(2-sqrt(2)) - 300. (End)
EXAMPLE
a(4) = 4*5*9*13*17/30 = 1326.
MATHEMATICA
a[n_] := n*(n+1)*(2*n+1)*(3*n+1)*(4*n+1)/30; Array[a, 30, 0] (* Amiram Eldar, Mar 08 2022 *)
PROG
(PARI) a(n) = n*(n+1)*(2*n+1)*(3*n+1)*(4*n+1)/30; \\ Michel Marcus, Aug 15 2013
CROSSREFS
Cf. A011195.
Sequence in context: A102196 A102192 A102197 * A286438 A224249 A361140
KEYWORD
easy,nonn
AUTHOR
Miklos Kristof, Jun 03 2004
EXTENSIONS
More terms from Michel Marcus, Aug 15 2013
STATUS
approved