OFFSET
0,2
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
R. P. Stanley, Examples of Magic Labelings, Unpublished Notes, 1973 [Cached copy, with permission]
Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).
FORMULA
G.f.: (1 + 12*x + 21*x^2 + 4*x^3) / (1 - x)^6.
From Colin Barker, Jan 11 2017: (Start)
a(n) = (n + 1)*(n + 2)*(19*n^3 + 63*n^2 + 68*n + 30) / 60.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>5.
(End)
MATHEMATICA
LinearRecurrence[{6, -15, 20, -15, 6, -1}, {1, 18, 114, 438, 1263, 3024}, 40] (* Harvey P. Dale, Nov 09 2022 *)
PROG
(PARI) Vec((1 + 12*x + 21*x^2 + 4*x^3) / (1 - x)^6 + O(x^40)) \\ Colin Barker, Jan 11 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Jul 07 2014
STATUS
approved