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.

A340205 Number of primes in A339443 among the values of A339443(k) for k = 1..n.

Original entry on oeis.org

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

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Author

Wesley Ivan Hurt, Dec 31 2020

Keywords

Examples

			a(12) = 6; The first 12 values of A339443 are 1, 1, 2, 1, 3, 1, 2, 2, 4, 1, 3, 2 (of which, 6 are prime).
		

Crossrefs

Formula

a(n) = Sum_{k=1..n} pi(c(k)) - pi(c(k)-1), where c = A339443.