A034794 a(n) is the least prime p > a(n-1) such that a(n-1) is a quadratic residue mod p.

2, 7, 19, 31, 41, 43, 53, 59, 67, 73, 79, 89, 97, 101, 107, 127, 139, 151, 163, 173, 179, 193, 197, 223, 241, 251, 283, 293, 307, 313, 317, 353, 383, 389, 409, 419, 443, 457, 461, 467, 487, 499, 521, 523, 571, 577, 593, 601, 607, 619, 631, 641, 643, 653, 659

Offset

1,1

Comments

a(n-1) is a term in row a(n) of A046071. - Reinhard Zumkeller, May 10 2015

Links

T. D. Noe, Table of n, a(n) for n=1..1000

Maple

f:= proc(t) local i, p;
  p:= t;
  do
    p:= nextprime(p);
    if numtheory:-jacobi(t, p) = 1 then return p fi
  od
end proc:
A[1]:= 2:
for n from 2 to 100 do A[n]:= f(A[n-1]) od:
seq(A[i], i=1..100); # Robert Israel, Sep 04 2016

Mathematica

f[n_] := Block[{k = PrimePi[n] + 1}, While[ JacobiSymbol[n, Prime[k]] == -1, k++ ]; Prime[k]]; NestList[f, 2, 54] (* Robert G. Wilson v, Mar 16 2004 *)

Prog

(Haskell)
a034794 n = a034794_list !! (n-1)
a034794_list = 2 : f 2 (tail  a000040_list) where
   f x (p:ps) = if elem x $ a046071_row p then p : f p ps else f x ps
-- Reinhard Zumkeller, May 10 2015

Crossrefs

Cf. A092581.

Cf. A046071, A000040.

Sequence in context: A144589 A179002 A232667 * A213892 A152608 A334520

Adjacent sequences: A034791 A034792 A034793 * A034795 A034796 A034797

Keyword

nonn,nice

Author

David W. Wilson

Extensions

Mathematica updated by Jean-François Alcover, Jul 04 2013

Name corrected by Robert Israel, Sep 04 2016

Status

approved