A375170 Primes that can be expressed as the sum of a prime and twice a positive square.

5, 7, 11, 13, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307

Offset

1,1

References

Albert H. Beiler, Recreations in the theory of numbers, New York, Dover, (2nd ed.) 1966. See p. 226.

Links

Table of n, a(n) for n=1..58.

Example

23 is a term since it equals 5 + 2*3^2.

Mathematica

a={}; For[i=1, i<=63, i++, For[j=1, (d=Prime[i]-2j^2)>0, j++, If[PrimeQ[d]&&!MemberQ[a, Prime[i]], AppendTo[a, Prime[i]]]]]; a

Crossrefs

Complement of A042978 in A000040.

Cf. A001105.

Sequence in context: A291345 A298867 A039681 * A216746 A084441 A180950

Adjacent sequences: A375167 A375168 A375169 * A375171 A375172 A375173

Keyword

nonn

Author

Stefano Spezia, Aug 16 2024

Status

approved