A144975 Centered heptagonal twin prime numbers.

43, 71, 197, 463, 1933, 5741, 8233, 9283, 11173, 14561, 34651, 41203, 57793, 68111, 84631, 104147, 139301, 168631, 207523, 244861, 307693, 333103, 357281, 415381, 465011, 475273, 506731, 592663, 595547, 607153, 729373, 742211, 781397, 876751

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Wikipedia, Centered heptagonal twin prime numbers

Example

43 is a term since it is centered heptagonal and the greater member of the twin primes pair (41, 43).
71 is a term since it is centered heptagonal and the lesser member of the twin primes pair (71, 73).

Mathematica

TwinPrimeQ[n_]:=If[PrimeQ[n], If[PrimeQ[n-2]||PrimeQ[n+2], True, False], False](*TwinPrimeQ*) lst={}; Do[p=(7*n^2-7*n+2)/2; If[TwinPrimeQ[p], AppendTo[lst, p]], {n, 2*6!}]; lst

Prog

(Magma) [a:k in [1..510]|IsPrime(a) and (IsPrime(a-2) or IsPrime(a+2)) where a is (7*k^2-7*k+2) div 2]; // Marius A. Burtea, Jan 30 2020

Crossrefs

Cf. A001097, A069099.

Sequence in context: A087765 A141971 A144974 * A087699 A054807 A285017

Adjacent sequences: A144972 A144973 A144974 * A144976 A144977 A144978

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Sep 27 2008

Status

approved