A331112 Sum of the digits of the n-th prime number in balanced ternary.

0, 1, -1, 1, 1, 3, -1, 1, -1, 1, 3, 3, -3, -1, -1, -1, -1, 1, 3, -1, 1, 1, 1, 1, 1, 1, 3, 1, 3, 1, -1, -3, -1, 1, -3, -1, 1, 1, -1, 1, -1, 1, 1, 3, 1, 3, 1, 1, 1, 3, -1, -1, 1, 1, -1, 1, 1, 3, 3, 3, 5, -1, 3, -1, 1, 1, 3, 5, 1, 3, 3, 3, -3, -1, -1, -3, -1, -1, -3, 1, -3, -1, -1, 1, 1, 1, -3, -1, -1, 1, -1, -1, 1, -1, 3, -1, -1, 1, 3, 1

Offset: 1

Author

Thomas König, Jan 09 2020

Keywords

• sign
• base
• easy

Examples

			Using T for -1 and _bt as suffix for balanced ternary: 2_10 = 1T_bt, sum of digits is zero; 3_10 = 10_bt, sum of digits is 1 and 5_10 = 1TT, sum of digits = -1.
		

Links

• Wikipedia, Balanced ternary

Crossrefs

See A007605 (sum of digits of primes in base 10); A239619 (sum of digits of primes in base 3).

Cf. A000040, A065363, A117966.

Programs

C

#include 
#include 
#define N 1000 /* Largest prime considered - 1  */
char x[N];
int main()
{
  int i, n, v, s, r;
  for (i=4; i
				

Maple

b:= proc(n) `if`(n=0, 0, (d-> `if`(d=2,
      b(q+1)-1, d+b(q)))(irem(n, 3, 'q')))
    end:
a:= n-> b(ithprime(n)):
seq(a(n), n=1..100);  # Alois P. Heinz, Jan 09 2020

Formula

a(n) = A065363(A000040(n)). - Alois P. Heinz, Jan 09 2020