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A106542 a(n) = a(n-1) - 2*a(n-2) - 3*a(n-3) - ... - (n-1)*a(1), beginning with 3. 1
3, 3, -3, -18, -33, -15, 84, 261, 333, -138, -1557, -3315, -2436, 6153, 24009, 36390, 1431, -129639, -323292, -318819, 400725, 2149686, 3807795, 1476405, -10310388, -30697599, -37588047, 20103078, 186854271, 384871329, 260548788, -769001739, -2840006499 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

LINKS

Colin Barker, Table of n, a(n) for n = 3..1000

FORMULA

Conjectures from Colin Barker, Dec 04 2015: (Start)

a(n) = 3*a(n-1)-5*a(n-2)+2*a(n-3) for n>5.

G.f.: 3*x^5*(1-x)^2 / (1-3*x+5*x^2-2*x^3).

(End)

EXAMPLE

a(5) = -18 + 6 - 9 - 12 = -33.

PROG

(PARI) a=vector(40); a[3]=3; for(n=4, #a, a[n]=a[n-1]-sum(k=2, n-3, k*a[n-k])); a[3..#a] \\ Colin Barker, Dec 04 2015

CROSSREFS

Sequence in context: A290159 A083562 A332860 * A342363 A229934 A239125

Adjacent sequences:  A106539 A106540 A106541 * A106543 A106544 A106545

KEYWORD

easy,sign

AUTHOR

Alexandre Wajnberg, May 08 2005

STATUS

approved

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Last modified June 13 10:21 EDT 2021. Contains 344985 sequences. (Running on oeis4.)