A174877 Larger of two distinct primes a and b such that a*b+-d are primes, and d is a difference between a and b.

7, 13, 17, 31, 73, 97, 113, 193, 211, 241, 277, 349, 353, 409, 449, 571, 601, 673, 769, 829, 997, 1009, 1039, 1129, 1201, 1291, 1381, 1409, 1429, 1753, 1861, 2089, 2137, 2341, 2393, 2633, 2689, 2713, 2797, 3001, 3109, 3121, 3169, 3361, 3433, 3457, 3529

Offset

1,1

Comments

2*3=6;3-2=1;6+1=7, 2*5=10;5-2=3;10+3=13, 3*5=15;5-3=2;15+2=17,..

Links

Table of n, a(n) for n=1..47.

Mathematica

lst={}; Do[pa=Prime[a]; Do[pb=Prime[b]; sp=pa*pb; dp=Abs[pa-pb]; If[PrimeQ[sp-dp]&&PrimeQ[sp+dp], AppendTo[lst, sp+dp]], {b, a+1, 5!}], {a, 5!}]; Union@lst

Crossrefs

Cf. A088708, A174873, A174874.

Sequence in context: A247010 A138337 A359063 * A230433 A029477 A019378

Adjacent sequences: A174874 A174875 A174876 * A174878 A174879 A174880

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Mar 31 2010

Status

approved