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A025257 (1/3)*s(n+3), where s = A025256. 0
1, 2, 6, 14, 35, 97, 264, 727, 2059, 5876, 16893, 49085, 143639, 422764, 1251642, 3724276, 11129680, 33393998, 100560903, 303812039, 920617337, 2797335154, 8521230447, 26017690537, 79610304979, 244082395820, 749739211746, 2306942230064 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..28.

FORMULA

G.f.: (1-x-x^2-6*x^3-sqrt(1-2*x-x^2-10*x^3+x^4))/x^3/6. - Vladeta Jovovic, May 07 2003

Conjecture: (n+3)*a(n) +(-2*n-3)*a(n-1) -n*a(n-2) +5*(-2*n+3)*a(n-3) +(n-3)*a(n-4)=0. - R. J. Mathar, Feb 25 2015

CROSSREFS

Sequence in context: A297187 A231509 A318018 * A283438 A323027 A110152

Adjacent sequences:  A025254 A025255 A025256 * A025258 A025259 A025260

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified September 28 14:44 EDT 2022. Contains 357073 sequences. (Running on oeis4.)