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A023830 Sum of exponents in prime-power factorization of C(4n,n-4). 1
0, 3, 4, 6, 6, 10, 8, 8, 8, 11, 12, 12, 13, 14, 15, 16, 12, 16, 15, 17, 18, 21, 17, 20, 19, 19, 22, 19, 21, 25, 25, 26, 23, 25, 25, 26, 26, 28, 25, 27, 25, 29, 28, 27, 31, 32, 31, 33, 30, 30, 31, 31, 31, 34, 32, 33, 32, 35, 35, 37, 39, 42, 42, 41, 37, 40, 41, 38, 42, 44, 40, 46, 42, 45, 46, 45, 44 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,2

LINKS

Ivan Neretin, Table of n, a(n) for n = 4..10000

FORMULA

a(n) = Omega( C(4n,n-4) ) = A001222( C(4n,n-4) ), n > 3.

MAPLE

with(numtheory): A023830:=n->bigomega(binomial(4*n, n-4)): seq(A023830(n), n=4..100); # Wesley Ivan Hurt, Oct 13 2014

MATHEMATICA

Join[{0}, Table[Total[Transpose[FactorInteger[Binomial[4n, n-4]]][[2]]], {n, 5, 80}]] (* Harvey P. Dale, Oct 12 2014 *)

PROG

(PARI) a(n) = bigomega(binomial(4*n, n-4)); \\ Michel Marcus, Oct 12 2014

CROSSREFS

Cf. A001222.

Sequence in context: A033095 A158907 A175708 * A063649 A053158 A206924

Adjacent sequences:  A023827 A023828 A023829 * A023831 A023832 A023833

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Offset changed by Wesley Ivan Hurt, Oct 13 2014

STATUS

approved

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Last modified March 25 22:28 EDT 2019. Contains 321477 sequences. (Running on oeis4.)