A023588 - OEIS

%I #16 May 30 2024 19:14:30

%S 1,1,2,1,2,2,2,1,3,2,1,1,4,2,2,3,3,2,2,2,2,1,3,2,1,2,2,2,2,4,2,3,3,1,

%T 4,2,1,3,3,3,3,2,2,3,2,1,1,2,2,1,3,3,2,2,4,4,2,1,2,3,2,4,1,4,4,2,1,1,

%U 4,2,3,2,1,2,1,4,3,2,3,2,4,2,3,2,1,3,3,2,2,3,2,3,2,3,1,3,3,2,3

%N a(n) = sum of exponents in prime-power factorization of 2*prime(n)-1.

%H Harvey P. Dale, <a href="/A023588/b023588.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = A001222(A076274(n)). - _R. J. Mathar_, Mar 10 2011

%t Array[Plus@@Last/@FactorInteger[2*Prime[ # ]-1]&,6! ] (* _Vladimir Joseph Stephan Orlovsky_, Feb 28 2010 *)

%t Table[Total[FactorInteger[2p-1][[;;,2]]],{p,Prime[Range[100]]}] (* _Harvey P. Dale_, May 30 2024 *)

%K nonn

%O 1,3

%A _Clark Kimberling_