A017855 - OEIS

A017855

Expansion of 1/(1-x^6-x^7-x^8-x^9-x^10-x^11-x^12-x^13-x^14-x^15).

1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 5, 6, 8, 11, 15, 20, 24, 29, 36, 46, 60, 79, 101, 127, 159, 200, 255, 328, 421, 537, 681, 861, 1092, 1391, 1776, 2267, 2888, 3670, 4661, 5925, 7542, 9609, 12242, 15584

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OFFSET

0,13

COMMENTS

Number of compositions of n into parts p where 6 <= p <= 15. [Joerg Arndt, Jun 28 2013]

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

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

FORMULA

a(n) = a(n-6) +a(n-7) +a(n-8) +a(n-9) +a(n-10) +a(n-11) +a(n-12) +a(n-13) +a(n-14) +a(n-15) for n>14. - Vincenzo Librandi, Jun 28 2013

MATHEMATICA

CoefficientList[Series[1 / (1 - Total[x^Range[6, 15]]), {x, 0, 60}], x] (* Vincenzo Librandi, Jun 28 2013 *)

PROG

(Magma) I:=[1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 2, 3, 4]; [n le 15 select I[n] else Self(n-6)+Self(n-7)+Self(n-8)+Self(n-9)+Self(n-10)+Self(n-11)+Self(n-12)+Self(n-13)+Self(n-14)+Self(n-15): n in [1..70]]; /* or */ m:=70; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/(1-x^6-x^7-x^8-x^9-x^10-x^11-x^12-x^13-x^14-x^15))); // Vincenzo Librandi, Jun 28 2013

CROSSREFS

Sequence in context: A017866 A086886 A017840 * A051598 A086993 A238714

Adjacent sequences: A017852 A017853 A017854 * A017856 A017857 A017858

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved