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A017898
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Expansion of (1-x)/(1-x-x^4).
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20
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1, 0, 0, 0, 1, 1, 1, 1, 2, 3, 4, 5, 7, 10, 14, 19, 26, 36, 50, 69, 95, 131, 181, 250, 345, 476, 657, 907, 1252, 1728, 2385, 3292, 4544, 6272, 8657, 11949, 16493, 22765, 31422, 43371, 59864, 82629, 114051, 157422, 217286, 299915, 413966, 571388, 788674
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OFFSET
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0,9
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COMMENTS
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A Lamé sequence of higher order.
Essentially the same as A003269, which has much more information.
Number of compositions of n into parts >= 4. - Joerg Arndt, Aug 13 2012
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LINKS
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FORMULA
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Apparently a(n) = hypergeometric([1-1/4*n, 5/4-1/4*n, 3/2-1/4*n, 7/4-1/4*n],[4/3-1/3*n, 5/3-1/3*n, 2-1/3*n], -4^4/3^3) for n>=13. - Peter Luschny, Sep 18 2014
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MAPLE
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f := proc(r) local t1, i; t1 := []; for i from 1 to r do t1 := [op(t1), 0]; od: for i from 1 to r+1 do t1 := [op(t1), 1]; od: for i from 2*r+2 to 50 do t1 := [op(t1), t1[i-1]+t1[i-1-r]]; od: t1; end; # set r = order
a:= n-> (Matrix(4, (i, j)-> if (i=j-1) then 1 elif j=1 then [1, 0$2, 1][i] else 0 fi)^n)[4, 4]: seq(a(n), n=0..42); # Alois P. Heinz, Aug 04 2008
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MATHEMATICA
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CoefficientList[Series[(1-x)/(1-x-x^4), {x, 0, 50}], x] (* Harvey P. Dale, Sep 12 2019 *)
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PROG
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(PARI) a(n)=([0, 1, 0, 0; 0, 0, 1, 0; 0, 0, 0, 1; 1, 0, 0, 1]^n*[1; 0; 0; 0])[1, 1] \\ Charles R Greathouse IV, Oct 03 2016
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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