A110487 Squares of the form p*q - p - q + 2, where p and q are primes.

9, 25, 49, 81, 121, 169, 225, 289, 361, 529, 625, 841, 961, 1225, 1369, 1521, 1681, 1849, 2025, 2209, 2401, 2601, 2809, 3025, 3481, 3721, 4225, 4489, 4761, 5041, 5329, 5929, 6241, 6889, 7225, 7921, 8281, 9025, 9409, 10201, 10609, 11449, 11881, 12769

Offset

1,1

Comments

Includes A108570 squares of lesser twin primes and A110284 squares of form 4p-3 where p is prime (q=5).

Links

Table of n, a(n) for n=1..44.

Mathematica

Lim=13000; f[{p_, q_}]:=p*q-p-q+2; Union[Select[f/@Subsets[Prime[Range[PrimePi[Lim]]], {2}], #<Lim&&IntegerQ[Sqrt[#]]&]] (* James C. McMahon, Apr 20 2024 *)

Crossrefs

Cf. A108570, A110284, A110484.

Sequence in context: A113745 A348742 A016754 * A377654 A259417 A030156

Adjacent sequences: A110484 A110485 A110486 * A110488 A110489 A110490

Keyword

nonn

Author

Giovanni Teofilatto, Sep 11 2005

Extensions

Corrected and extended by Ray Chandler, Sep 13 2005

Status

approved