A118591 Larger of two consecutive primes whose sum is a square.

19, 53, 73, 293, 883, 1153, 1931, 2593, 3529, 4051, 6053, 7207, 7451, 15139, 20809, 21647, 24203, 26921, 28807, 34849, 46819, 53147, 56453, 69193, 74507, 83233, 84053, 98573, 103067, 103969, 109517, 110459, 112339, 136247, 149059, 151253

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..600 from Harvey P. Dale)

Formula

a(n) = A151800(A061275(n)). - Amiram Eldar, Jul 12 2024

Example

17 and 19 are consecutive primes whose sum is 36, a square, so 19 is a term.

Mathematica

Transpose[Select[Partition[Prime[Range[14000]], 2, 1], IntegerQ[ Sqrt[ Total[#]]]&]] [[2]] (* Harvey P. Dale, May 03 2012 *)

Prog

(PARI) g(n) = for(x=2, n, if(issquare(prime(x)+prime(x-1)), print1(prime(x)", ")))
(PARI) lista(pmax) = {my(p1 = 2); forprime(p2 = 3, pmax, if(issquare(p1 + p2), print1(p2, ", ")); p1 = p2); } \\ Amiram Eldar, Jul 12 2024

Crossrefs

Cf. A061275, A151800.

Sequence in context: A190267 A373008 A066775 * A031341 A165982 A194431

Adjacent sequences: A118588 A118589 A118590 * A118592 A118593 A118594

Keyword

easy,nonn

Author

Cino Hilliard, May 08 2006

Status

approved