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A027151
a(n) = T(n,0) + T(n,1) + ... + T(n,n), T given by A027144.
2
1, 3, 7, 21, 45, 135, 291, 873, 1881, 5643, 12159, 36477, 78597, 235791, 508059, 1524177, 3284145, 9852435, 21229047, 63687141, 137226717, 411680151, 887047443, 2661142329, 5733964809, 17201894427, 37064931183, 111194793549, 239591481525, 718774444575
OFFSET
0,2
FORMULA
G.f.: (1 + 3*x)*(1 + x^2) / (1 - 6*x^2 - 3*x^4).
a(n) = 6*a(n-2) + 3*a(n-4) for n>3. - Colin Barker, Jan 18 2018
PROG
(PARI) Vec((1 + 3*x)*(1 + x^2) / (1 - 6*x^2 - 3*x^4) + O(x^40)) \\ Colin Barker, Jan 18 2018
CROSSREFS
Cf. A141041 (bisection), A287811 (bisection).
Sequence in context: A329114 A018712 A183936 * A219589 A092203 A018760
KEYWORD
nonn,easy
STATUS
approved