A023854 Sum of exponents in prime-power factorization of binomial(6n, 3n).
0, 3, 5, 6, 7, 11, 11, 12, 13, 14, 15, 16, 15, 19, 20, 21, 22, 23, 23, 22, 25, 29, 25, 29, 28, 31, 32, 30, 31, 34, 34, 35, 35, 36, 36, 38, 38, 41, 41, 41, 40, 46, 44, 43, 44, 44, 46, 47, 46, 47, 50, 51, 49, 53, 49, 52, 53, 53, 56, 55, 56, 60, 60, 61, 57, 61, 61, 61, 65, 66, 63, 67, 66, 69, 69, 66, 69, 71, 70, 72, 72
Offset: 0
Keywords
Links
- Ivan Neretin, Table of n, a(n) for n = 0..10000
Programs
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Mathematica
Join[{0}, Total[Transpose[FactorInteger[Binomial[6 #, 3 #]]][[2]]]&/@Range[80]] (* Harvey P. Dale, May 14 2011 *) a[n_] := PrimeOmega[Binomial[6*n, 3*n]]; Array[a, 100, 0] (* Amiram Eldar, Jun 11 2025 *)
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PARI
a(n) = bigomega(binomial(6*n, 3*n)); \\ Amiram Eldar, Jun 11 2025
Formula
From Amiram Eldar, Jun 11 2025: (Start)
Extensions
Corrected and extended by Harvey P. Dale, May 14 2011
a(0)=0 inserted by Amiram Eldar, Jun 11 2025