A251859 First appearance of prime(n) in A157480.

1, 6, 5, 10, 3, 2, 8, 7, 13, 20, 30, 28, 27, 26, 35, 58, 45, 56, 55, 21, 96, 142, 53, 93, 262, 14, 139, 12, 195, 47, 87, 57, 214, 404, 133, 255, 81, 252, 37, 36, 187, 128, 127, 479, 75, 572, 477, 313, 70, 475, 179, 68, 241, 310, 19, 98, 115, 469, 762, 114, 234, 94, 302, 231, 1238, 229, 298, 376, 50, 161

Offset: 1

Author

Zak Seidov, Dec 10 2014

Keywords

• nonn

Comments

Apparently all primes eventually appear in A157480. Note that this sequence is one-to-one map while A157480 not.

Examples

			a(3)=5 because A157480(5)=prime(3)=5 and prime(3)+prime(5)=5+11=16=4^2,
a(4)=10 because A157480(10)=prime(4)=7 and prime(4)+prime(10)=7+29=36=6^2.
		

Crossrefs

Cf. A157480.

Formula

A157480(a(n)) = prime(n), or prime(a(n))+prime(n) is a square.