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A010016
a(0) = 1, a(n) = 26*n^2 + 2 for n>0.
1
1, 28, 106, 236, 418, 652, 938, 1276, 1666, 2108, 2602, 3148, 3746, 4396, 5098, 5852, 6658, 7516, 8426, 9388, 10402, 11468, 12586, 13756, 14978, 16252, 17578, 18956, 20386, 21868, 23402, 24988, 26626, 28316, 30058, 31852, 33698, 35596, 37546, 39548, 41602
OFFSET
0,2
FORMULA
G.f.: (1+x)*(1+24*x+x^2)/(1-x)^3. - Bruno Berselli, Feb 06 2012
E.g.f.: (x*(x+1)*26+2)*e^x-1. - Gopinath A. R., Feb 14 2012
Sum_{n>=0} 1/a(n) = 3/4+sqrt(13)/52*Pi*coth(Pi/sqrt 13) = 1.060279759190266417... - R. J. Mathar, May 07 2024
MATHEMATICA
Join[{1}, 26 Range[40]^2 + 2] (* Bruno Berselli, Feb 06 2012 *)
CROSSREFS
Cf. A206399.
Sequence in context: A263200 A223443 A201469 * A256647 A223492 A219857
KEYWORD
nonn,easy
AUTHOR
STATUS
approved