id:A063681 - OEIS Search Results

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Primes p such that 2p+7 is a power of three.

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37, 265717, 193710241, 1270932914161, 187855106306818130162790081799568953899918191769361, 884821727139988111281341588371104523273965529248966451172919369920848760385637 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`If (3^i-7)/2 is prime then x=3^i-7 is a solution of sigma(x)+7 = sigma(x+7). See A063680 and indices resulting in primes are in A063679.`
	FORMULA	`2*37+7 = 3^4, so 37 is in the sequence.`
	CROSSREFS	`Cf. A063679, A063680.` `Sequence in context: A015061 A015037 A140746 this_sequence A087020 A023930 A022072` `Adjacent sequences: A063678 A063679 A063680 this_sequence A063682 A063683 A063684`
	KEYWORD	`nonn`
	AUTHOR	`Jud McCranie (j.mccranie(AT)comcast.net), Jul 29 2001`

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Last modified November 25 14:49 EST 2009. Contains 167514 sequences.

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