A174878 - OEIS

A174878

Primes in A174874 and A174877.

7, 13, 73, 193, 241, 349, 409, 673, 769, 1201, 2089, 2689, 2713, 3109, 3169, 3181, 3361, 3433, 3529, 4057, 4129, 4153, 4201, 4561, 4801, 5281, 5581, 5641, 5821, 6133, 6421, 6469, 6529, 6709, 6841, 7561, 7753, 8161, 8929, 9241, 9601, 9697, 9769, 10321

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OFFSET

1,1

COMMENTS

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

LINKS

Table of n, a(n) for n=1..44.

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, 6!}], {a, 6!}]; lst1=Union@lst; 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, 6!}], {a, 6!}]; lst2=Union@lst; Intersection[lst1, lst2]

CROSSREFS

Cf. A088708, A174873, A174874, A174877.

Sequence in context: A106976 A219908 A098478 * A177198 A177163 A268350

Adjacent sequences: A174875 A174876 A174877 * A174879 A174880 A174881

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Mar 31 2010

STATUS

approved