A341043 a(n) = 16*n^3 - 36*n^2 + 30*n - 9.
1, 35, 189, 559, 1241, 2331, 3925, 6119, 9009, 12691, 17261, 22815, 29449, 37259, 46341, 56791, 68705, 82179, 97309, 114191, 132921, 153595, 176309, 201159, 228241, 257651, 289485, 323839, 360809, 400491, 442981, 488375, 536769, 588259, 642941, 700911, 762265
Offset: 1
Examples
For n = 3 the solution is 173 + 8 + 8 = 189.
Links
- Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
Programs
-
PARI
Vec(x*(9*x^3+55*x^2+31*x+1)/(x-1)^4 + O(x^38)) \\ Elmo R. Oliveira, Sep 01 2025
Formula
a(n) = 16*n^3 - 36*n^2 + 30*n - 9.
G.f.: x*(1 + 31*x + 55*x^2 + 9*x^3)/(1 - x)^4. - Stefano Spezia, Feb 04 2021
From Elmo R. Oliveira, Sep 01 2025: (Start)
E.g.f.: 9 + exp(x)*(-9 + 10*x + 12*x^2 + 16*x^3).
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). (End)
Extensions
More terms from Elmo R. Oliveira, Sep 01 2025
Comments