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A162757
a(n) = 12*a(n-1)-33*a(n-2) for n > 1; a(0) = 1, a(1) = 7.
2
1, 7, 51, 381, 2889, 22095, 169803, 1308501, 10098513, 78001623, 602768547, 4659169005, 36018666009, 278471414943, 2153041001019, 16646935319109, 128712870795681, 995205584017575, 7694942271953427, 59497522990861149
OFFSET
0,2
COMMENTS
Sixth binomial transform of A108411. Binomial transform of A162558. Inverse binomial transform of A162758.
FORMULA
a(n) = ((3+sqrt(3))*(6+sqrt(3))^n+(3-sqrt(3))*(6-sqrt(3))^n)/6.
G.f.: (1-5*x)/(1-12*x+33*x^2).
PROG
(Magma) [ n le 2 select 6*n-5 else 12*Self(n-1)-33*Self(n-2): n in [1..20] ];
CROSSREFS
Cf. A108411 (powers of 3 repeated), A162558, A162758.
Sequence in context: A034354 A015555 A137382 * A285880 A147958 A104454
KEYWORD
nonn
AUTHOR
Klaus Brockhaus, Jul 13 2009
STATUS
approved