A161188 Let S = A089237\{0} = union of primes and nonzero squares; sequence gives indices of primes.

2, 3, 5, 6, 8, 9, 11, 12, 13, 15, 16, 18, 19, 20, 21, 23, 24, 25, 27, 28, 29, 30, 32, 33, 34, 36, 37, 38, 39, 40, 42, 43, 44, 45, 47, 48, 49, 50, 51, 53, 54, 55, 56, 57, 59, 60, 61, 62, 64, 65, 66, 67, 68, 69, 71, 72, 73, 74, 75, 76, 77, 79, 80, 81, 82, 83, 85, 86, 87, 88, 89

Offset: 1

Author

Daniel Tisdale, Jun 06 2009

Keywords

• easy
• nonn

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A089237. Complement of A161187.

Cf. A050051.

Programs

Haskell

a161188 n = a161188_list !! (n-1)
a161188_list = map (+ 1) $ findIndices ((== 1) . a010051) $ tail a089237_list
-- Reinhard Zumkeller, Dec 18 2012

Python

from math import isqrt
from sympy import prime
def A161188(n): return n+isqrt(prime(n)) # Chai Wah Wu, Oct 12 2024

Formula

A089237(a(n)+1) = A000040(n). - Reinhard Zumkeller, Dec 18 2012

a(n) = floor(sqrt(prime(n))) + n. - Ilya Gutkovskiy, Feb 16 2017

Extensions

Edited by N. J. A. Sloane, Jun 07 2009

Extended by Ray Chandler, May 06 2010