A097143 a(n) is the least prime greater than a(n-1) such that n is a quadratic residue mod p.

2, 7, 11, 13, 19, 23, 29, 31, 37, 41, 43, 47, 53, 61, 67, 71, 83, 89, 101, 109, 127, 137, 173, 191, 193, 197, 227, 233, 239, 241, 251, 257, 263, 269, 271, 277, 293, 313, 317, 347, 349, 353, 383, 389, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 463, 479

Offset

1,1

Comments

a(10^n): 2,41,1229,16693,220721,2734801,32393839,..., .

Conjecture: Lim_n->Inf a(n)/A097144(n) = 1 <==> a(P_2n).

Links

Table of n, a(n) for n=1..56.

Eric Weisstein's World of Mathematics, Quadratic Residue.

Mathematica

a[1] = 2; a[n_] := a[n] = Block[{k = PrimePi[ a[n - 1]] + 1}, While[ JacobiSymbol[n, Prime[k]] != 1, k++ ]; Prime[k]]; Table[ a[n], {n, 20}]

Crossrefs

Cf. A097152. Complement of A097144.

Sequence in context: A191052 A338173 A138889 * A038897 A161681 A020583

Adjacent sequences: A097140 A097141 A097142 * A097144 A097145 A097146

Keyword

nonn

Author

Robert G. Wilson v, Jul 26 2004

Status

approved