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A137357 a(n) = Sum_{k <= n/2 } binomial(n-2k, 3k+1). 2
0, 1, 2, 3, 4, 5, 7, 12, 23, 44, 80, 138, 230, 379, 629, 1060, 1810, 3109, 5336, 9120, 15521, 26349, 44713, 75949, 129177, 219918, 374521, 637699, 1085401, 1846804, 3141826, 5344988, 9093989, 15474230, 26332515, 44810670, 76253683, 129755543, 220790480 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

REFERENCES

D. E. Knuth, The Art of Computer Programming, Vol. 4A, Section 7.1.4.

LINKS

Table of n, a(n) for n=0..38.

Index entries for linear recurrences with constant coefficients, signature (3,-3,1,0,1).

FORMULA

G.f.: x*(x-1) / (x^5+x^3-3*x^2+3*x-1). - Colin Barker, Jan 23 2013

CROSSREFS

Cf. A137356-A137361, A136444.

Sequence in context: A060437 A133428 A090703 * A100676 A193769 A226790

Adjacent sequences:  A137354 A137355 A137356 * A137358 A137359 A137360

KEYWORD

nonn,easy

AUTHOR

Don Knuth, Apr 11 2008

STATUS

approved

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Last modified February 25 04:05 EST 2018. Contains 299630 sequences. (Running on oeis4.)