OFFSET
2,1
COMMENTS
For a guide to related sequences, see A206817.
LINKS
Danny Rorabaugh, Table of n, a(n) for n = 2..10000
Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).
FORMULA
a(n) = n^5-p(n), where p(n) is the n-th partial sum of (j^4).
a(n) = t(n)-t(n-1), where t = A206811.
a(n) = (n-10*n^3-15*n^4+24*n^5)/30. G.f.: x^2*(x^3+25*x^2+55*x+15) / (x-1)^6. - Colin Barker, Jul 11 2014
EXAMPLE
a(2) = 2^4-1^4 = 15.
a(3) = (3^4-1^4) + (3^4-2^4) = 145.
MATHEMATICA
PROG
(PARI) Vec(x^2*(x^3+25*x^2+55*x+15)/(x-1)^6 + O(x^100)) \\ Colin Barker, Jul 11 2014
(Sage) [sum([n^4-j^4 for j in range(1, n)]) for n in range(2, 30)] # Danny Rorabaugh, Apr 18 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Feb 15 2012
STATUS
approved