cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A340203 Number of primes in A339399 among the values of A339399(k) for k = 1..n.

Original entry on oeis.org

0, 0, 0, 1, 1, 2, 3, 4, 4, 4, 5, 6, 6, 7, 8, 8, 9, 10, 10, 10, 11, 12, 13, 13, 13, 14, 15, 15, 16, 17, 17, 17, 17, 17, 18, 19, 20, 20, 20, 21, 21, 21, 22, 22, 23, 24, 24, 24, 25, 26, 26, 26, 27, 27, 28, 28, 28, 29, 30, 30, 30, 31, 32, 32, 33, 33, 33, 33, 34, 35, 35, 35, 35
Offset: 1

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Author

Wesley Ivan Hurt, Dec 31 2020

Keywords

Examples

			a(14) = 7; There are 7 primes that are less than or equal to A339399(n). For example, the first 14 values of A339399(n) are 1, 1, 1, 2, 1, 3, 2, 2, 1, 4, 2, 3, 1 and 5 (7 of which are prime).
		

Crossrefs

Formula

a(n) = Sum_{k=1..n} pi(c(k)) - pi(c(k)-1), where c = A339399.