A023820 Sum of exponents in prime-power factorization of C(3n,n-1).

0, 2, 4, 4, 4, 7, 7, 8, 8, 8, 11, 12, 9, 12, 13, 12, 11, 13, 14, 15, 14, 17, 18, 19, 16, 18, 20, 18, 18, 21, 20, 21, 19, 20, 22, 22, 19, 22, 24, 22, 21, 24, 27, 29, 28, 28, 29, 31, 27, 28, 29, 29, 28, 34, 32, 32, 31, 30, 34, 34, 32, 34, 36, 35, 31, 32, 31, 33, 33, 36, 35, 36, 32, 36, 40, 37, 36, 38

Offset

1,2

Links

Ivan Neretin, Table of n, a(n) for n = 1..10000

Mathematica

Join[{0}, Table[Total[FactorInteger[Binomial[3 n, n - 1]][[All, 2]]], {n, 2, 78}]] (* Ivan Neretin, Nov 02 2017 *)

Crossrefs

Sequence in context: A035545 A327333 A371910 * A225355 A117726 A172307

Adjacent sequences: A023817 A023818 A023819 * A023821 A023822 A023823

Keyword

nonn

Author

Clark Kimberling

Status

approved