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A187012 Antidiagonal sums of A103516. 2
1, 2, 5, 4, 8, 6, 11, 8, 14, 10, 17, 12, 20, 14, 23, 16, 26, 18, 29, 20, 32, 22, 35, 24, 38, 26, 41, 28, 44, 30, 47, 32, 50, 34, 53, 36, 56, 38, 59, 40, 62, 42, 65, 44, 68, 46, 71, 48, 74, 50, 77, 52, 80, 54, 83, 56, 86, 58, 89, 60, 92, 62, 95, 64 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

COMMENTS

This sequence differs from A081556 at least for n=24 (see comment about n=24 in A081556).

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 2..1000

FORMULA

a(n) = sum{k=0..floor(n/2), 0^(k(n-2k))*(n-k+1)}. - Paul Barry, Aug 30 2013

G.f. : x^2*(1+2*x+3*x^2-x^4)/((1-x)^2*(1+x)^2).

a(n) = A080512(n) - 1 for n>2.

MATHEMATICA

CoefficientList[Series[(1 + 2 x + 3 x^2 - x^4)/((1 - x)^2 (1 + x)^2), {x, 0, 40}], x] (* Vincenzo Librandi, Jun 24 2014 *)

PROG

(PARI) a(n) = sum(k=0, n\2, 0^(k*(n-2*k))*(n-k+1)); \\ Michel Marcus, Aug 30 2013

CROSSREFS

Sequence in context: A206256 A093052 A081556 * A134079 A033686 A243973

Adjacent sequences:  A187009 A187010 A187011 * A187013 A187014 A187015

KEYWORD

nonn,easy

AUTHOR

Michel Marcus, Aug 30 2013

STATUS

approved

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Last modified October 17 21:16 EDT 2019. Contains 328132 sequences. (Running on oeis4.)