A340294 a(n) = pi(A340063(n)) = A000720(A340063(n)) for prime A340063(n) and otherwise k such that A340063 is the k-th positive integer having its digitsum.

1, 1, 2, 2, 3, 3, 3, 4, 1, 5, 5, 6, 2, 4, 7, 6, 8, 3, 5, 9, 1, 10, 7, 11, 2, 6, 12, 3, 13, 8, 14, 4, 7, 15, 2, 16, 3, 17, 9, 18, 4, 8, 19, 5, 20, 10, 21, 4, 22, 5, 9, 23, 5, 24, 1, 25, 6, 10, 26, 11, 27, 7, 28, 12, 29, 7, 11, 30, 1, 6, 31, 8, 32, 6, 33, 13, 34, 2

Offset: 1

Author

David A. Corneth, Jan 03 2021

Keywords

• nonn
• base

Examples

			a(17) = 8 as A340063(17) = 19 which is the 8th prime.
a(25) = 2 as A340063(25) = 14 which is composite and 14 is the second positive integer with digitsum 5.
		

Links

• David A. Corneth, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000720, A254524, A340063.