A333788 Semiprimes whose both factors are Fermat primes.

9, 15, 25, 51, 85, 289, 771, 1285, 4369, 66049, 196611, 327685, 1114129, 16843009, 4295098369

Offset: 1

Author

Antti Karttunen, Apr 15 2020

Keywords

• nonn

Comments

Product of two, not necessarily distinct Fermat primes.

For the finiteness or non-finiteness of this sequence, see A019434.

Most terms are binary palindromes (in A006995), except among the fifteen known terms, these squares > 9 are not: 25, 289, 66049, 4295098369.

Crossrefs

Cf. A006995, A019434.

Subsequence of A334102.