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A134142
List of quadruples: 2*(-4)^n, -3*(-4)^n, 2*(-4^n), 2*(-4)^n, n >= 0.
3
2, -3, 2, 2, -8, 12, -8, -8, 32, -48, 32, 32, -128, 192, -128, -128, 512, -768, 512, 512, -2048, 3072, -2048, -2048, 8192, -12288, 8192, 8192, -32768, 49152, -32768, -32768, 131072, -196608, 131072, 131072, -524288, 786432, -524288, -524288, 2097152, -3145728, 2097152, 2097152, -8388608
OFFSET
0,1
FORMULA
O.g.f.: (x+2)/(2*x^2+2*x+1). a(n) = 2*A108520(n)+A108520(n-1). - R. J. Mathar, Feb 05 2008
a(n) = (1 - I/2)*(-1 - I)^n + (1 + I/2)*(-1 + I)^n, n>=0. - Taras Goy, Apr 20 2019
MAPLE
A134142 := proc(n) (-4)^floor(n/4)*op(1+(n mod 4), [2, -3, 2, 2]) ; end: for n from 0 to 80 do printf("%d ", A134142(n)) ; od: # R. J. Mathar, Feb 05 2008
CROSSREFS
Sequence in context: A151863 A365407 A366782 * A353390 A298310 A138680
KEYWORD
tabf,easy,sign
AUTHOR
Paul Curtz, Jan 29 2008
EXTENSIONS
More terms from R. J. Mathar, Feb 05 2008
STATUS
approved