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A360417
a(n) = 8*n^2 - 7*n + 2.
3
2, 3, 20, 53, 102, 167, 248, 345, 458, 587, 732, 893, 1070, 1263, 1472, 1697, 1938, 2195, 2468, 2757, 3062, 3383, 3720, 4073, 4442, 4827, 5228, 5645, 6078, 6527, 6992, 7473, 7970, 8483, 9012, 9557, 10118, 10695, 11288, 11897, 12522, 13163, 13820, 14493, 15182
OFFSET
0,1
COMMENTS
This is one of the four quadratic sequences that, interleaved, yield A360418.
FORMULA
From Elmo R. Oliveira, Jan 28 2025: (Start)
G.f.: (17*x^2-3*x+2)/(1-x)^3.
E.g.f.: exp(x)*(2 + x + 8*x^2).
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n >= 3.
a(n) = A360418(4*n-1) for n>=1. (End)
a(n) = A125201(n) + 1, n >= 1. - Omar E. Pol, Jan 28 2025
MATHEMATICA
Table[8*n^2 - 7*n + 2, {n, 0, 100}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
James Propp, Feb 06 2023
EXTENSIONS
a(0)=2 prepended and more terms from Alois P. Heinz, Jan 28 2025
STATUS
approved