id:A138510 - OEIS Search Results

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Smallest number b such that in base b representation the prime factors of the n-th semiprime (A001358) have equal lengths.

+0
5

1, 2, 1, 6, 8, 3, 3, 12, 1, 14, 12, 18, 2, 20, 14, 24, 1, 18, 4, 20, 30, 32, 4, 24, 38, 4, 42, 5, 44, 30, 4, 32, 48, 5, 54, 38, 5, 60, 5, 1, 62, 42, 44, 5, 68, 48, 72, 2, 30, 74, 32, 80, 54, 5, 84, 1, 60, 90, 62, 38, 3, 98, 68, 102, 6, 42, 104, 3, 72, 108, 44, 6, 110, 74, 3, 114, 48, 80 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`a(n) = 1 iff A001358(n) is a prime square (A001248);` `a(A138511(n)) = A084127(A138511(n)) + 1.`
	EXAMPLE	`n=91=7*13: 7 = '111'[binary] = '21'[ternary] = '13'[base4]` `and 13 = '1101'[binary] = '111'[ternary] = '31'[base4],` `therefore 91 is a term, a(31) = 91.`
	CROSSREFS	`Cf. A078972, A085721.` `Sequence in context: A112007 A113374 A136470 this_sequence A026215 A026220 A138750` `Adjacent sequences: A138507 A138508 A138509 this_sequence A138511 A138512 A138513`
	KEYWORD	`nonn,base`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Mar 21 2008`

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Last modified July 24 12:00 EDT 2008. Contains 142294 sequences.

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