A055419 Number of points in N^n of norm <= 4.
1, 5, 17, 54, 165, 482, 1319, 3390, 8262, 19250, 43154, 93601, 197381, 406200, 817954, 1614348, 3126068, 5943728, 11103912, 20396957, 36869790, 65637607, 115178814, 199377387, 340708159, 575150851, 959691775, 1583660542
Offset: 0
Links
- Andrew Howroyd, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (17,-136,680,-2380,6188,-12376,19448,-24310,24310,-19448,12376,-6188,2380,-680,136,-17,1).
Crossrefs
Row n=4 of A302998.
Formula
Empirical g.f.: (11*x^16 -164*x^15 +936*x^14 -2841*x^13 +5310*x^12 -6697*x^11 +6044*x^10 -3984*x^9 +1734*x^8 -75*x^7 -741*x^6 +827*x^5 -539*x^4 +235*x^3 -68*x^2 +12*x -1) / (x -1)^17. - Colin Barker, Jul 07 2013