A373607 Sum of the odd-indexed digits in the primorial base representation (A049345) of n.

0, 0, 1, 1, 2, 2, 0, 0, 1, 1, 2, 2, 0, 0, 1, 1, 2, 2, 0, 0, 1, 1, 2, 2, 0, 0, 1, 1, 2, 2, 1, 1, 2, 2, 3, 3, 1, 1, 2, 2, 3, 3, 1, 1, 2, 2, 3, 3, 1, 1, 2, 2, 3, 3, 1, 1, 2, 2, 3, 3, 2, 2, 3, 3, 4, 4, 2, 2, 3, 3, 4, 4, 2, 2, 3, 3, 4, 4, 2, 2, 3, 3, 4, 4, 2, 2, 3, 3, 4, 4, 3, 3, 4, 4, 5, 5, 3, 3, 4, 4, 5, 5, 3, 3, 4, 4

Offset: 0

Author

Antti Karttunen, Jun 18 2024

Keywords

• nonn

Examples

			A049345(85) = 2401, and the sum of digits at the odd positions  (with the rightmost digit having index 0) is 0+2 = 2, thus a(85) = 2.
		

Links

• Antti Karttunen, Table of n, a(n) for n = 0..16170
• Index entries for sequences related to primorial base

Crossrefs

Cf. A049345, A276150, A373605, A373606.

Programs

PARI

A373607(n) = { my(p=2, i=0, s=0); while(n, if(i%2, s += (n%p)); n = n\p; p = nextprime(1+p); i = !i); (s); };

Formula

a(n) = A276150(n) - A373606(n).

a(n) = A373606(n) - A373605(n).