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A174262 Primes of the form 21^(2^n) + 2. 0
23, 443, 194483 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) is congruent 3 mod 4.

The next term (if it exists) corresponds to some n>23, so it has more than 11 million digits. [R. J. Mathar, Aug 23 2010]

LINKS

Table of n, a(n) for n=1..3.

CROSSREFS

Cf. A057726, A152589.

Sequence in context: A203147 A158453 A291128 * A174425 A076068 A062273

Adjacent sequences:  A174259 A174260 A174261 * A174263 A174264 A174265

KEYWORD

nonn,bref

AUTHOR

Giovanni Teofilatto, Mar 14 2010

EXTENSIONS

Entries checked. - R. J. Mathar, Aug 23 2010

STATUS

approved

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Last modified July 29 17:41 EDT 2021. Contains 346346 sequences. (Running on oeis4.)