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A086972 a(n) = n*3^(n-1) + (3^n+1)/2. 2
1, 3, 11, 41, 149, 527, 1823, 6197, 20777, 68891, 226355, 738113, 2391485, 7705895, 24712007, 78918989, 251105873, 796364339, 2518233179, 7942120025, 24988621541, 78452649023, 245818300271, 768835960421, 2400651060089 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Binomial transform of A057711 (without leading zero). Second binomial transform of (1,1,3,3,5,5,7,7,9,9,11,11,...).

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..400

Index entries for linear recurrences with constant coefficients, signature (7,-15,9).

FORMULA

G.f.: (1-4*x+5*x^2)/((1-x)*(1-3*x)^2).

a(n) = A027471(n) + A007051(n).

PROG

(MAGMA) [n*3^(n-1) + (3^n+1)/2: n in [0..30]]; // Vincenzo Librandi, Jun 09 2011

(PARI) Vec((1-4*x+5*x^2)/((1-x)*(1-3*x)^2) + O(x^40)) \\ Michel Marcus, Mar 08 2016

CROSSREFS

Equals (1/2) [A081038(n) + 1].

Sequence in context: A075276 A242233 A294504 * A218348 A320827 A077831

Adjacent sequences:  A086969 A086970 A086971 * A086973 A086974 A086975

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Jul 26 2003

STATUS

approved

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Last modified December 11 23:44 EST 2019. Contains 329945 sequences. (Running on oeis4.)