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A037508
Base 7 digits are, in order, the first n terms of the periodic sequence with initial period 1,2,0.
0
1, 9, 63, 442, 3096, 21672, 151705, 1061937, 7433559, 52034914, 364244400, 2549710800, 17847975601, 124935829209, 874550804463, 6121855631242, 42852989418696, 299970925930872, 2099796481516105
OFFSET
1,2
FORMULA
G.f.: x*(1+2*x) / ( (x-1)*(7*x-1)*(1+x+x^2) ). - R. J. Mathar, Apr 27 2015
PROG
(PARI) a(n)=([0, 1, 0, 0; 0, 0, 1, 0; 0, 0, 0, 1; -7, 1, 0, 7]^(n-1)*[1; 9; 63; 442])[1, 1] \\ Charles R Greathouse IV, Feb 13 2017
CROSSREFS
Sequence in context: A339786 A201885 A225964 * A037691 A206816 A336670
KEYWORD
nonn,base,easy
STATUS
approved