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A165283
a(n) = (2*n + 1)*16^n.
2
1, 48, 1280, 28672, 589824, 11534336, 218103808, 4026531840, 73014444032, 1305670057984, 23089744183296, 404620279021568, 7036874417766400, 121597189939003392, 2089670227099910144, 35740566642812256256, 608742554432415203328, 10330176681277348904960
OFFSET
0,2
FORMULA
G.f.: (1+16*x)/(1-16*x)^2.
Sum_{n>=0} 1/a(n) = 2*log(5/3).
Sum_{n>=0} (-1)^n/a(n) = 4 * arctan(1/4). - Amiram Eldar, Jul 12 2020
E.g.f.: exp(16*x)*(1 + 32*x). - Stefano Spezia, May 09 2023
PROG
(PARI) a(n)=(2*n+1)*16^n
(Magma) [(2*n+1)*16^n: n in [0..20]]; // Vincenzo Librandi, Jun 08 2011
CROSSREFS
Cf. A058962 ((2n+1)4^n), A155988 ((2n+1)9^n).
Sequence in context: A082558 A285169 A163272 * A141407 A004341 A222199
KEYWORD
nonn,easy
AUTHOR
Jaume Oliver Lafont, Sep 13 2009
STATUS
approved