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A122583 a(n) = a(n - 1) - 2*a(n - 2) + a(n - 3) + 3*(-2*a(n - 4) + a(n - 5)). 1
1, 1, 1, 1, 1, -3, -7, -3, 5, 25, 45, -3, -107, -191, -175, 253, 1045, 1189, -171, -3547, -7527, -4603, 11497, 33945, 40869, -10487, -141071, -248407, -120131, 421141, 1227961, 1332777, -726439, -5051271, -8369959, -3306635, 16738977, 43110597, 41391949, -33360335, -183387403, -283721435 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

This recursion is inspired by Ulam's early experiments in derivative recursions.

LINKS

Table of n, a(n) for n=1..42.

Index entries for linear recurrences with constant coefficients, signature (1,-2,1,-6,3).

FORMULA

G.f.:(-1-7*x^4-x^3-2*x^2)*x/(-1+3*x^5-6*x^4+x^3-2*x^2+x). - Maksym Voznyy (voznyy(AT)mail.ru), Aug 11 2009

MAPLE

A122583 := proc(n) option remember ; if n <= 5 then 1; else A122583(n-1)-2*A122583(n-2)+A122583(n-3)+3*(-2*A122583(n-4)+A122583(n-5)) ; fi ; end: seq(A122583(n), n=1..80) ; # R. J. Mathar, Sep 18 2007

MATHEMATICA

a[0] = 1; a[1] = 1; a[2] = 1; a[3] = 1; a[4] = 1; a[n_] := a[n] = a[n - 1] - 2*a[n - 2] + a[n - 3] + 3*(-2*a[n - 4] + a[n - 5]); Table[a[n], {n, 0, 30}]

CROSSREFS

Sequence in context: A193534 A096247 A337013 * A001265 A060443 A020810

Adjacent sequences:  A122580 A122581 A122582 * A122584 A122585 A122586

KEYWORD

sign

AUTHOR

Roger L. Bagula, Sep 19 2006

EXTENSIONS

Edited by N. J. A. Sloane, Oct 01 2006

More terms from R. J. Mathar, Sep 18 2007

STATUS

approved

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Last modified July 25 00:32 EDT 2021. Contains 346273 sequences. (Running on oeis4.)