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A131949
Row sums of triangle A131948.
2
1, 6, 16, 32, 56, 92, 148, 240, 400, 692, 1244, 2312, 4408, 8556, 16804, 33248, 66080, 131684, 262828, 525048, 1049416, 2098076, 4195316, 8389712, 16778416, 33555732, 67110268, 134219240, 268437080, 536872652, 1073743684, 2147485632, 4294969408, 8589936836
OFFSET
0,2
FORMULA
Binomial transform of (1, 5, 5, 1, 1, 1, ...).
G.f.: 1-2*x*(-3+7*x-3*x^2+x^3) / ( (2*x-1)*(x-1)^3 ). - R. J. Mathar, Apr 04 2012
From Colin Barker, Nov 04 2017: (Start)
a(n) = 2^n + 2*n + 2*n^2.
a(n) = 5*a(n-1) - 9*a(n-2) + 7*a(n-3) - 2*a(n-4) for n > 3.
(End)
EXAMPLE
a(3) = 32 = sum of row 3 terms, triangle A131948: (7 + 9 + 9 + 7).
a(3) = 32 = (1, 3, 3, 1) dot (1, 5, 5, 1) = (1 + 15 + 15 + 1).
MATHEMATICA
LinearRecurrence[{5, -9, 7, -2}, {1, 6, 16, 32}, 30] (* Harvey P. Dale, Feb 24 2016 *)
PROG
(PARI) Vec((1 + x - 5*x^2 - x^3) / ((1 - x)^3*(1 - 2*x)) + O(x^40)) \\ Colin Barker, Nov 04 2017
CROSSREFS
Cf. A131948.
Sequence in context: A301713 A134465 A036488 * A345023 A243763 A061235
KEYWORD
nonn,easy
AUTHOR
Gary W. Adamson, Jul 30 2007
STATUS
approved