A132329 Numbers that cannot be expressed as the difference of the squares of primes.

1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, 42, 43, 44, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 80

Offset

1,2

Comments

Complement of A124865.

Links

Table of n, a(n) for n=1..72.

Mathematica

lim=80; sp={4}; i=2; Until[Prime[i]^2-(Prime[i]-2)^2>lim, AppendTo[sp, Prime[i]^2]; i++]; Complement[Range[lim], Union[Differences/@Subsets[sp, {2}]//Flatten]] (* James C. McMahon, Mar 08 2025 *)

Crossrefs

Cf. A124865, A090781.

Sequence in context: A231237 A053241 A340288 * A230313 A052413 A276389

Adjacent sequences: A132326 A132327 A132328 * A132330 A132331 A132332

Keyword

nonn,changed

Author

Rick L. Shepherd, Aug 19 2007

Status

approved