A093625 - OEIS

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A093625

Primes of the form (3^n+1)/2.

2, 5, 41, 21523361, 926510094425921, 1716841910146256242328924544641 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`1,1`
	COMMENTS	`Primes can only occur for n=2^k. The next term (if it exists) has k>=21 (i.e. more than 10^6 decimal digits). - Don Reble (djr(AT)nk.ca), Apr 28 2004. [For the latest results about the search, see A171381. - N. J. A. Sloane, Jun 14 2010]`
	LINKS	`Table of n, a(n) for n=1..6.`
	EXAMPLE	`a(3)=41 because it can be written as (3^4+1)/2=82/2.`
	CROSSREFS	`A171381 is the main entry for this sequence. Cf. also A138083.` `Sequence in context: A076725 A059917 A255963 * A042447 A176266 A075872` `Adjacent sequences: A093622 A093623 A093624 * A093626 A093627 A093628`
	KEYWORD	`nonn,hard`
	AUTHOR	`Hugo Pfoertner, Apr 19 2004`
	EXTENSIONS	`Erroneous terms deleted by N. J. A. Sloane, Jun 14 2010`
	STATUS	`approved`

Last modified August 20 23:34 EDT 2017. Contains 290855 sequences.