A277385 Records in A277384.
15, 33, 65, 105, 153, 209, 273, 345, 425, 513, 609, 713, 825, 945, 1073, 1209, 1353, 1505, 1665, 1833, 2009, 2193, 2385, 2585, 2793, 3009, 3233, 3465, 3705, 3953, 4209, 4473, 4745, 5025, 5313, 5609, 5913, 6225, 6545, 6873, 7209, 7553, 7905, 8265, 8633, 9009
Offset: 1
Links
- Colin Barker, Table of n, a(n) for n = 1..1000
- Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
Crossrefs
Cf. A277384.
Programs
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Mathematica
Join[{15}, LinearRecurrence[{3, -3, 1}, {33, 65, 105}, 25]] (* or *) Join[{15}, Table[4*n^2 + 12*n - 7, {n,2,25}]] (* G. C. Greubel, Oct 12 2016 *) -
PARI
Vec(x*(15-12*x+11*x^2-6*x^3)/(1-x)^3 + O(x^60))
Formula
G.f.: x*(15 -12*x +11*x^2 -6*x^3) / (1-x)^3.
E.g.f.: 7 + 6*x + (4*x^2 + 16*x - 7)*exp(x). - G. C. Greubel, Oct 12 2016
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>4.
a(n) = 4*n^2 + 12*n - 7 for n>1.
Comments