A192688 - OEIS

%I #29 May 05 2019 03:24:08

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

%T 3,3,3,3,3,3,3,4,3,3,3,3,3,3,3,3,4,3,3,3,3,3,4,3,3,3,3,3,3,4,3,3,3,3,

%U 3,3,3,3,4,3,3,3,3,3,3,4,3,3,3,3,4,3,3

%N Sum of omega-values for two consecutive indices where they equal the omega-value at the sum of the two indices.

%C The sequence contains sums A001221(n) + A001221(n+1) whenever they are equal to A001221(2n+1).

%C Generated by indices n = 1, 7, 16, 31, 52, 82, 97, 136, 157, 172, 178, 192, 199, 232, 241, 256, 262, 277, 292, ...

%p for n from 1 to 2000 do

%p         if A001221(n)+A001221(n+1) = A001221(2*n+1) then

%p                 printf("%d,",A001221(2*n+1)) ;

%p         end if;

%p end do: # _R. J. Mathar_, Oct 12 2011

%t f[n_] := Block[{a = PrimeNu[n] + PrimeNu[n + 1]}, If[a == PrimeNu[2n + 1], Return@ a]]; k = 1; lst = {}; While[k < 2600, If[f@k > 0, AppendTo[lst, f@ k]]; k++]; lst (* _Robert G. Wilson v_, Aug 29 2011 *)

%Y Cf. A001221, A059957, A092523.

%K nonn

%O 1,2

%A _Juri-Stepan Gerasimov_, Jul 07 2011