A025548 a(n) = sum of the exponents in the prime factorization of the least common multiple of {1,3,5,...,2n-1}.

0, 1, 2, 3, 4, 5, 6, 6, 7, 8, 8, 9, 10, 11, 12, 13, 13, 13, 14, 14, 15, 16, 16, 17, 18, 18, 19, 19, 19, 20, 21, 21, 21, 22, 22, 23, 24, 24, 24, 25, 26, 27, 27, 27, 28, 28, 28, 28, 29, 29, 30, 31, 31, 32, 33, 33, 34, 34, 34, 34, 35, 35, 36, 37, 37, 38, 38, 38, 39, 40, 40, 40, 40

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A001222, A025547.

Programs

Maple

N:= 100: # for a(1) .. a(N)
V:= Vector(N):
p:= 2:
do
  p:= nextprime(p);
  if p > 2*N-1 then break fi;
  J:= [seq((p^i+1)/2, i = 1 .. ilog[p](2*N-1))];
  V[J]:= V[J] +~ 1;
od:
ListTools:-PartialSums(convert(V,list)); # Robert Israel, Dec 26 2024

Formula

a(n) = A001222(A025547(n)).

Extensions

Corrected and extended by Ray Chandler, May 01 2007