A097492 -id:A097492 - cp's OEIS frontend

A097493 Primes which are two greater than A097492 terms.

7, 37, 457, 8647, 51315414607

Offset: 1

Cino Hilliard, Aug 24 2004

nonn

The next term (17866..79237) has 186 digits.

			a(4) = 8647 = (Product_{k=1..4} A006512(k)) + 2 = 5*7*13*19 + 2 = A097492(4) + 2. - _Hartmut F. W. Hoft_, Apr 27 2021

Amiram Eldar, Table of n, a(n) for n = 1..7

Cf. A097490, A097491, A097492.

Cf. A001359, A077800, A097489.

step[{list_, q_}] := Module[{p=NextPrime[q]}, {Join[list, If[PrimeQ[p+2], {{p,p+2}}, {}]], p}]
largerTwin[n_] := Last[Transpose[First[NestWhile[step, {{{3, 5}}, 3}, Length[First[step[#]]]<=n&]]]]
a097492[n_] := Rest[FoldList[Times, 1, largerTwin[n]]]
a097493[n_] := Select[Map[#+2&, a097492[n]], PrimeQ]
a097493[68] (* Hartmut F. W. Hoft, Apr 27 2021 *)

fu(n) = p=1;for(x=1,n,p*=twinu(x);if(isprime(p+2),print1(p+2", ")))
twinu(n) = { local(c,x); c=0; x=1; while(c

Edited by Don Reble, Apr 16 2007

A097489 a(n) = product of first n terms of A001359.

Original entry on oeis.org

3, 15, 165, 2805, 81345, 3335145, 196773555, 13970922405, 1411063162905, 150983758430835, 20684774905024395, 3082031460848634855, 551683631491905639045, 105371573614953977057595, 20758200002145933480346215, 4712111400487126900038590805

Offset: 1

Cino Hilliard, Aug 24 2004

nonn

Amiram Eldar, Table of n, a(n) for n = 1..279

Cf. A001359, A097492.

FoldList[Times,Select[Partition[Prime[Range[50]],2,1],#[[2]]-#[[1]]==2&][[All,1]]] (* Harvey P. Dale, Oct 09 2020 *)

twinl(n) = { local(c,x); c=0; x=1; while(c

Edited by Don Reble, Apr 16 2007

a(15)-a(16) from Amiram Eldar, Jul 07 2024

cp's OEIS Frontend

A097493 Primes which are two greater than A097492 terms.

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