A104260 Sum of odd digits (1,3,5,7,9) of n-th prime.

0, 3, 5, 7, 2, 4, 8, 10, 3, 9, 4, 10, 1, 3, 7, 8, 14, 1, 7, 8, 10, 16, 3, 9, 16, 2, 4, 8, 10, 5, 8, 5, 11, 13, 10, 7, 13, 4, 8, 11, 17, 2, 11, 13, 17, 19, 2, 3, 7, 9, 6, 12, 1, 6, 12, 3, 9, 8, 14, 1, 3, 12, 10, 5, 7, 11, 7, 13, 10, 12, 11, 17, 10, 13, 19, 6, 12, 19, 1, 9, 10, 1, 4, 6, 12, 3, 9, 12

Offset: 1

Author

Zak Seidov, Feb 26 2005

Keywords

• nonn
• base

Crossrefs

Sum of even digits (2, 4, 6, 8) of n-th prime: A104261, sum of prime digits (2, 3, 5, 7) of n-th prime: A104250, sum of composite (nonprime) digits (1, 4, 6, 8, 9) of n-th prime: A104251, sum of digits of primes: A007605, primes: A000040.

Programs

Mathematica

sodod={};Do[id=IntegerDigits[Prime[i]];lid=Length[id];sod=Sum[If[OddQ[id[[k]]], id[[k]], 0], {k, lid}];sodod={sodod, sod}, {i, 200}];sodod//Flatten
f[n_] := Plus @@ Select[ IntegerDigits[ Prime[n]], OddQ[ # ] &]; Table[ f[n], {n, 88}] (* Robert G. Wilson v, Nov 03 2005 *)

Formula

a(n) = A007605(n) - A104261(n).