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A108082
Sum_{i=0..n} binomial(2n+i,2i).
0
1, 4, 26, 176, 1204, 8273, 56967, 392688, 2708322, 18683233, 128892764, 889172365, 6133354976, 42300883471, 291696384929, 2011120962840, 13863370486596, 95548230542403, 658416136868846, 4536321401562529
OFFSET
0,2
FORMULA
a(n) ~ phi^(4*n + 1) / sqrt(5), where phi = A001622 = (1 + sqrt(5))/2 is the golden ratio. - Vaclav Kotesovec, Apr 12 2018
MATHEMATICA
Table[Sum[Binomial[2n+i, 2i], {i, 0, n}], {n, 0, 20}] (* Harvey P. Dale, Apr 12 2018 *)
CROSSREFS
Sequence in context: A220305 A210911 A278416 * A199490 A116429 A084134
KEYWORD
nonn
AUTHOR
Ralf Stephan, Jun 03 2005
STATUS
approved