

A333788


Semiprimes whose both factors are Fermat primes.


5



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

1,1


COMMENTS

Product of two, not necessarily distinct Fermat primes.
For the finiteness or nonfiniteness 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.


LINKS

Table of n, a(n) for n=1..15.


CROSSREFS

Cf. A006995, A019434.
Subsequence of A334102.
Sequence in context: A109888 A193227 A014003 * A082549 A013569 A129401
Adjacent sequences: A333785 A333786 A333787 * A333789 A333790 A333791


KEYWORD

nonn


AUTHOR

Antti Karttunen, Apr 15 2020


STATUS

approved



