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A122709 Self-convolution of A122553. 3
1, 6, 15, 24, 33, 42, 51, 60, 69, 78, 87, 96, 105, 114, 123, 132, 141, 150, 159, 168, 177, 186, 195, 204, 213, 222, 231, 240, 249, 258, 267, 276, 285, 294, 303, 312, 321, 330, 339, 348, 357, 366, 375, 384, 393, 402, 411, 420, 429, 438, 447, 456, 465, 474, 483 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..54.

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

FORMULA

a(0)=1, a(n)=9*n-3=A008591(n)-3 for n>0 . a(0)=1, a(1)=6, a(2)=15, a(n)=2*a(n-1)-a(n-2) for n>2 . a(0)=1, a(1)=6, a(n)=a(n-1)+9 for n>1 . G.f. ((1+2*x)/(1-x))^2.

Equals binomial transform of [1, 5, 4, -4, 4, -4, 4,...]. - Gary W. Adamson, Dec 10 2007

MATHEMATICA

Join[{1}, LinearRecurrence[{2, -1}, {6, 15}, 60]] (* Harvey P. Dale, Jun 12 2012 *)

PROG

(PARI) a(n)=max(9*n-3, 1) \\ Charles R Greathouse IV, Jan 17 2012

CROSSREFS

Sequence in context: A043477 A055040 A017233 * A052220 A217747 A242405

Adjacent sequences:  A122706 A122707 A122708 * A122710 A122711 A122712

KEYWORD

nonn,easy

AUTHOR

Philippe Deléham, Sep 23 2006

STATUS

approved

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Last modified March 27 06:50 EDT 2017. Contains 284144 sequences.