A155932 Integers a(n) such that cube(n)-square(x) and cube(n)+square(x) are primes.

3, 6, 7, 8, 10, 13, 15, 18, 20, 21, 22, 28, 33, 35, 37, 39, 42, 43, 45, 48, 52, 57, 58, 60, 62, 63, 68, 72, 73, 75, 77, 78, 80, 82, 83, 85, 86, 87, 90, 91, 92, 93, 95, 97, 99, 102, 103, 105, 106, 107, 108, 111, 112, 113, 115, 117, 120, 123, 125, 128, 129, 132, 133, 135

Offset

1,1

Comments

3^3-2^2=23;3^3+2^2=31, 6^3-5^2=191;6^3+5^2=241, 7^3-6^2=307;7^3+6^2=379, ...

Links

Table of n, a(n) for n=1..64.

Mathematica

lst={}; Do[k=n; c=n^3; Label[ax]; s=k^2; p1=c-s; p2=c+s; If[PrimeQ[p1]&&PrimeQ[p2], AppendTo[lst, n], k--; If[k>0, Goto[ax]]], {n, 2*5!}]; lst

Crossrefs

Cf. A155929, A155930, A155931

Sequence in context: A295566 A266986 A047283 * A298980 A206586 A347878

Adjacent sequences: A155929 A155930 A155931 * A155933 A155934 A155935

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Jan 30 2009

Status

approved