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A016863
a(n) = (5*n + 1)^3.
3
1, 216, 1331, 4096, 9261, 17576, 29791, 46656, 68921, 97336, 132651, 175616, 226981, 287496, 357911, 438976, 531441, 636056, 753571, 884736, 1030301, 1191016, 1367631, 1560896, 1771561, 2000376, 2248091, 2515456, 2803221, 3112136, 3442951, 3796416, 4173281, 4574296
OFFSET
0,2
LINKS
FORMULA
Sum_{n>=0} 1/a(n) = -polygamma(2, 1/5)/250. - Amiram Eldar, Oct 02 2020
From Wesley Ivan Hurt, Oct 02 2020: (Start)
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4).
G.f.: (1+212*x+473*x^2+64*x^3)/(-1+x)^4. (End)
From Stefano Spezia, Nov 01 2024: (Start)
a(n) = A000578(A016861(n)).
E.g.f.: exp(x)*(1 + 215*x + 450*x^2 + 125*x^3). (End)
EXAMPLE
a(0) = (5*0 + 1)^3 = 1.
MATHEMATICA
Table[(5*n + 1)^3, {n, 0, 25}] (* Amiram Eldar, Oct 02 2020 *)
CROSSREFS
KEYWORD
nonn,easy,changed
STATUS
approved