A175013 Sum of digits of n-th semiprime.

4, 6, 9, 1, 5, 6, 3, 4, 7, 8, 6, 7, 8, 11, 12, 10, 13, 6, 10, 12, 13, 8, 11, 15, 11, 14, 10, 13, 14, 15, 10, 12, 13, 14, 7, 3, 7, 10, 11, 4, 5, 6, 12, 7, 8, 6, 7, 8, 10, 11, 11, 14, 15, 8, 13, 16, 15, 16, 12, 14, 16, 14, 3, 4, 5, 7, 8, 11, 6, 7, 8, 10, 11, 12, 5, 10, 10, 12, 13, 15, 10

Offset: 1

Author

Juri-Stepan Gerasimov, Apr 04 2010

Keywords

• nonn
• base

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A001358, A007953.

Programs

Maple

seq( A007953(A001358(n)),n=1..120) ; # R. J. Mathar, Aug 12 2010

Mathematica

Total[IntegerDigits[#]]&/@Select[Range[300],PrimeOmega[#]==2&] (* Harvey P. Dale, Jun 12 2012 *)

Formula

a(n) = A007953(A001358(n)).

Extensions

Entries checked by R. J. Mathar, Aug 12 2010