OFFSET
0,3
COMMENTS
Partial sums of centered 11-gonal (or hendecagonal) pyramidal numbers.
LINKS
OEIS Wiki, Figurate numbers
Eric Weisstein's World of Mathematics, Pyramidal Number
Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).
FORMULA
G.f.: x*(1 + 9*x + x^2)/(1 - x)^5.
a(n) = Sum_{k = 0..n} A004467(k).
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5). - Vincenzo Librandi, Nov 27 2015
MATHEMATICA
Table[n (n + 1) (11 n^2 + 11 n - 10)/24, {n, 0, 50}]
PROG
(Magma) [n*(n+1)*(11*n^2+11*n-10)/24: n in [0..50]]; // Vincenzo Librandi, Nov 27 2015
(PARI) a(n)=n*(n+1)*(11*n^2+11*n-10)/24 \\ Charles R Greathouse IV, Jul 26 2016
CROSSREFS
Cf. A004467.
KEYWORD
nonn,easy
AUTHOR
Ilya Gutkovskiy, Nov 26 2015
STATUS
approved