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Search: id:A052156
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| 1, 1, 4, 12, 36, 108, 324, 972, 2916, 8748, 26244, 78732, 236196, 708588, 2125764, 6377292, 19131876, 57395628, 172186884, 516560652, 1549681956, 4649045868, 13947137604, 41841412812, 125524238436, 376572715308, 1129718145924
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OFFSET
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0,3
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REFERENCES
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A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 189, 194-196.
P. Ribenhoim, The Little Book of Big Primes, Springer-Verlag, N.Y., 1991, p. 53.
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FORMULA
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a(n) = 4*3^(n-2); n >= 2; a(0) = 1; a(1) = 1.
a(n) = 3a(n-1)+[(-1)^n]*C(2, 2-n); g.f.(x) = (1-x)^2/(1-3x).
a(n)=A003946(n-1), n>0. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 13 2008]
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CROSSREFS
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Cf. A025192, A000244 and A003462.
Sequence in context: A001394 A156946 A003946 this_sequence A000781 A055395 A113990
Adjacent sequences: A052153 A052154 A052155 this_sequence A052157 A052158 A052159
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KEYWORD
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easy,nonn
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AUTHOR
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Barry E. Williams, Jan 24 2000
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