A139225 M(M-1)/3, where M is Mersenne prime A000668(n).

2, 14, 310, 5334, 22361430, 5726491990, 91625444694, 1537228670661645654, 1772303994379887828232566404493432150, 127707961738824071529862251643555745658871456065738070, 8776024305713098891493168973639040433964428736682367693182293334, 9649340769776349618630915417390658987602357538676244438223111363610210030934

Offset: 1

Author

Omar E. Pol, May 10 2008

Keywords

• nonn

Comments

Terms from a(13) on have 314 or more digits and are not listed for that reason. - R. J. Mathar, May 11 2008

Crossrefs

Cf. A000668, A036689, A139115, A139116, A139223, A139224, A139226.

Formula

a(n)=A000668(n)*(A000668(n)-1)/3.

Extensions

More terms from R. J. Mathar, May 11 2008