A246934 The closest square to n-th prime.

1, 4, 4, 9, 9, 16, 16, 16, 25, 25, 36, 36, 36, 49, 49, 49, 64, 64, 64, 64, 81, 81, 81, 81, 100, 100, 100, 100, 100, 121, 121, 121, 144, 144, 144, 144, 169, 169, 169, 169, 169, 169, 196, 196, 196, 196, 225, 225, 225, 225, 225, 225, 256, 256, 256, 256, 256, 256, 289, 289, 289, 289

Offset

1,2

Links

Zak Seidov, Table of n, a(n) for n = 1..1000

Example

a(5) = 9 because 5th prime is 11, and 11-9<16-11, that is 9 is the closest square to 11.

Prog

(PARI){forprime (p = 2, 300, a = sqrtint (p); b = (a + 1)^2; a = a^2;
   s = if (b - p > p - a, a, b); print1 (s ", "))}

Crossrefs

Sequence in context: A162564 A014694 A065730 * A206919 A168039 A145445

Adjacent sequences: A246931 A246932 A246933 * A246935 A246936 A246937

Keyword

nonn

Author

Zak Seidov, Oct 02 2014

Status

approved