id:A065725 - OEIS Search Results

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Primes p such that the decimal expansion of its base 7 conversion is also prime.

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2, 3, 5, 17, 29, 31, 43, 59, 71, 127, 157, 197, 211, 227, 239, 241, 337, 353, 367, 379, 409, 463, 491, 563, 577, 619, 647, 743, 757, 773, 787, 857, 911, 953, 967, 1093, 1123, 1163, 1193, 1249, 1303, 1373, 1429, 1459, 1471, 1499, 1583, 1597, 1613, 1627, 1669 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`In general rebase notation (Marc LeBrun): p(n) = (7) [p] (10).`
	EXAMPLE	`E.g. 787{10} = 2203{7} is prime but also 2203{10}.`
	MATHEMATICA	`Select[ Range[2500], PrimeQ[ # ] && PrimeQ[ FromDigits[ IntegerDigits[ #, 7]]] & ]`
	CROSSREFS	`Cf. A065720 up to A065727, A065361.` `Sequence in context: A055472 A077499 A127061 this_sequence A057468 A127062 A029972` `Adjacent sequences: A065722 A065723 A065724 this_sequence A065726 A065727 A065728`
	KEYWORD	`nonn,base`
	AUTHOR	`Patrick De Geest (pdg(AT)worldofnumbers.com), Nov 15 2001.`

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.

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