A111309 Absolute difference between the sum of the odd digits and the sum of the even digits of the n-th prime.

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

Offset: 1

Author

Zak Seidov and Robert G. Wilson v, Mar 02 2005

Keywords

• nonn
• base

Examples

			a(9)=1 because the 9th prime is 23 and the absolute difference between 2 & 3 is 1.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000
• Ivars Peterson, Light Rings

Crossrefs

Cf. A071650, A076167.

Programs

Maple

f:= proc(n) local Lo,Le;
  Lo,Le:= selectremove(type,convert(n,base,10),odd);
  abs(convert(Lo,`+`)-convert(Le,`+`))
end proc:
map(f, [seq(ithprime(i),i=1..100)]); # Robert Israel, Nov 12 2024

Mathematica

f[n_] := (id = IntegerDigits[ Prime[n]]; Abs[(Plus @@ id) - 2Plus @@ Select[id, OddQ]]); Table[f[n], {n, 91}]

Extensions

Edited by Charles R Greathouse IV, Aug 04 2010