A108604 Squares of the form prime(k)*prime(k+1) + 2*prime(k+1).

25, 49, 169, 361, 961, 1849, 3721, 5329, 10609, 11881, 19321, 22801, 32761, 37249, 39601, 52441, 58081, 73441, 80089, 97969, 121801, 177241, 187489, 214369, 273529, 326041, 361201, 383161, 413449, 436921, 657721, 677329, 687241, 737881, 779689

Offset

1,1

Comments

Squares of greater of twin primes.

Links

Winston de Greef, Table of n, a(n) for n = 1..10000

Formula

a(n) = A006512(n)^2.

Maple

ZL:=[]:for p from 1 to 950 do if (isprime(p) and isprime(p+2)) then ZL:=[op(ZL), ((p+2)^2)]; fi; od; print(ZL); # Zerinvary Lajos, Mar 08 2007

Mathematica

Select[Sqrt/@Table[Prime[k]*Prime[k+1]+2Prime[k+1], {k, 160}], IntegerQ]^2 (* James C. McMahon, Jan 27 2024 *)

Crossrefs

Cf. A006512, A108570.

Sequence in context: A046949 A137659 A020325 * A046950 A146641 A171590

Adjacent sequences: A108601 A108602 A108603 * A108605 A108606 A108607

Keyword

easy,nonn

Author

Giovanni Teofilatto, Jul 06 2005

Extensions

Corrected and extended by Ray Chandler, Jul 10 2005

Status

approved