[seqfan] Need help with A242866

Neil Sloane njasloane at gmail.com
Sat Sep 2 20:59:28 CEST 2023

Harvey Dale points out that there is a problem with A242866

The old definition was
Semiprimes of the form 2^(2^k) + 1 or 2^(2^k) + 2 for some k >= 0. +30
with terms
6, 10, 34, 514, 131074, 4294967297, 18446744073709551617,
The definition does not explain 10.  So I have replaced the definition with
the old comment, which is:

Union of 2*A019434 and the semiprimes in A000215.

Two things: can someone check if this new definition matches the terms? Can
someone create a new sequence to match the old definition?

More information about the SeqFan mailing list