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 A171408 a(n) = A171373(n+1) - 2*A171373(n). 1
 4, 4, 4, 4, 0, -12, -32, -52, -52, 0, 136, 356, 576, 576, 0, -1508, -3948, -6388, -6388, 0, 16724, 43784, 70844, 70844, 0, -185472, -485572, -785672, -785672, 0, 2056916, 5385076, 8713236, 8713236, 0, -22811548, -59721408, -96631268, -96631268, 0, 252983944, 662320564 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS The least significant digits have a period of length 20. Another period (not the same but of the same length, as this a sequence contains negative numbers) is defined reading the sequence modulo 10. LINKS Index entries for linear recurrences with constant coefficients, signature (3,-4,2,-1) FORMULA a(n)=4*A105371(n-1), n>0. a(n)= 3*a(n-1) -4*a(n-2) +2*a(n-3) -a(n-4). G.f.: 4*(1-2*x+2*x^2)/(1-3*x+4*x^2-2*x^3+x^4). CROSSREFS Cf. A138112, A105371. Sequence in context: A274947 A331961 A279406 * A071907 A172369 A190338 Adjacent sequences:  A171405 A171406 A171407 * A171409 A171410 A171411 KEYWORD sign AUTHOR Paul Curtz, Dec 08 2009 EXTENSIONS Edited and extended by R. J. Mathar, Mar 02 2010 STATUS approved

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Last modified July 2 01:17 EDT 2022. Contains 354984 sequences. (Running on oeis4.)