A082670 a(n) = p(n)!/2 where p(n) is the upper member of n-th pair of twin primes.

60, 2520, 3113510400, 60822550204416000, 4111419327088961408862781440000000, 30207631531686917818677566034256998753632256000000000

Offset

1,1

Links

Table of n, a(n) for n=1..6.

Formula

a(n) = A006512(n)! / 2. - Sean A. Irvine, Dec 18 2025

Mathematica

#!/2&/@Select[Partition[Prime[Range[50]], 2, 1], #[[2]]-#[[1]]==2&][[All, 2]] (* Harvey P. Dale, Nov 27 2016 *)

Prog

(PARI) tpperm2(n) = { forprime(x=3, n, if(isprime(x-2), print1(x!/2" ") ) ) }

Crossrefs

Cf. A006512.

Sequence in context: A075917 A058929 A057848 * A084659 A230568 A180373

Adjacent sequences: A082667 A082668 A082669 * A082671 A082672 A082673

Keyword

easy,nonn

Author

Cino Hilliard, May 18 2003

Extensions

Offset changed by Sean A. Irvine, Dec 18 2025

Status

approved