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

1,3

Links

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

Example

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.

Crossrefs

Cf. A000720, A254524, A340063.

Sequence in context: A128586 A130971 A051776 * A270920 A262956 A073734

Adjacent sequences: A340291 A340292 A340293 * A340295 A340296 A340297

Keyword

nonn,base

Author

David A. Corneth, Jan 03 2021

Status

approved