

A023819


Sum of exponents in primepower factorization of C(3n,n).


2



1, 2, 4, 4, 4, 6, 8, 6, 7, 8, 11, 11, 11, 11, 12, 10, 12, 11, 15, 13, 13, 18, 18, 17, 16, 17, 19, 17, 18, 19, 22, 18, 18, 20, 21, 19, 21, 22, 23, 22, 21, 23, 28, 27, 27, 28, 30, 27, 28, 26, 28, 29, 28, 31, 32, 29, 31, 31, 35, 32, 33, 35, 34, 31, 30, 31, 34, 31, 32, 35, 36, 33, 34, 35, 38, 37, 36, 36
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OFFSET

1,2


COMMENTS

Equivalently, sum of exponents of primes in multinomial coefficient M(3n; n,n,n)/C(2n,n).


LINKS

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


MAPLE

with(numtheory):(combinat):a:=proc(n) if n=0 then 0 else bigomega(binomial(3*n, n)) fi end: seq(a(n), n=1..78); # Zerinvary Lajos, Apr 11 2008


MATHEMATICA

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


CROSSREFS

Sequence in context: A033825 A235790 A023988 * A201629 A033827 A008217
Adjacent sequences: A023816 A023817 A023818 * A023820 A023821 A023822


KEYWORD

nonn


AUTHOR

Clark Kimberling


EXTENSIONS

Edited by N. J. A. Sloane at the suggestion of R. J. Mathar, May 31 2008


STATUS

approved



