A174874 Smaller prime number of two distinct primes a and b such that a*b+-d are primes, and d is a difference between a and b.

5, 7, 13, 41, 61, 73, 139, 181, 193, 229, 241, 349, 389, 409, 433, 457, 463, 569, 577, 661, 673, 709, 769, 881, 1021, 1049, 1117, 1201, 1249, 1321, 1801, 1873, 2029, 2089, 2113, 2281, 2389, 2473, 2521, 2593, 2689, 2857, 3109, 3169, 3181, 3301, 3313, 3361

Offset

1,1

Comments

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

Links

Table of n, a(n) for n=1..48.

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.

Sequence in context: A063446 A339775 A064600 * A109904 A077781 A102872

Adjacent sequences: A174871 A174872 A174873 * A174875 A174876 A174877

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Mar 31 2010

Status

approved