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A049858 a(n) = Sum{a(k): k=0,1,2,...,n-4,n-2,n-1}; a(n-3) is not a summand; 3 initial terms required. 3
0, 1, 2, 3, 5, 9, 17, 32, 60, 112, 209, 390, 728, 1359, 2537, 4736, 8841, 16504, 30809, 57513, 107363, 200421, 374138, 698426, 1303794, 2433871, 4543454, 8481540, 15833003, 29556423, 55174760, 102998057, 192272694, 358927051 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..33.

Index entries for linear recurrences with constant coefficients, signature (2,0,-1,1).

FORMULA

a(n) = 2*a(n-1) -a(n-3) +a(n-4); 4 initial terms required.

G.f. x*(x-1)*(1+x) / ( -1+2*x-x^3+x^4 ). - R. J. Mathar, Nov 12 2012

a(n) = A059633(n+2)-A059633(n). - R. J. Mathar, Aug 16 2017

PROG

(PARI) a(n)=([0, 1, 0, 0; 0, 0, 1, 0; 0, 0, 0, 1; 1, -1, 0, 2]^n*[0; 1; 2; 3])[1, 1] \\ Charles R Greathouse IV, Aug 16 2017

CROSSREFS

Pairwise sums of A049856. Partial sums of A049864.

Sequence in context: A054187 A014743 A080889 * A092483 A324767 A005257

Adjacent sequences:  A049855 A049856 A049857 * A049859 A049860 A049861

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified July 23 19:33 EDT 2019. Contains 325263 sequences. (Running on oeis4.)