id:A059054 - OEIS Search Results

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Integers which can be written as (b^k+1)/(b+1) for positive integers b and k.

+0
2

1, 3, 7, 11, 13, 21, 31, 43, 57, 61, 73, 91, 111, 133, 157, 171, 183, 205, 211, 241, 273, 307, 343, 381, 421, 463, 507, 521, 547, 553, 601, 651, 683, 703, 757, 813, 871, 931, 993, 1057, 1111, 1123, 1191, 1261, 1333, 1407, 1483, 1561, 1641, 1723, 1807, 1893 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`It seems that all values are odd. For (b^k+1)/(b+1) to be an integer, it seems k must be odd. 2=(0^0+1)/(0+1) has been excluded since neither b nor k would be positive.`
	LINKS	`H. Dubner and T. Granlund, Primes of the Form (b^n+1)/(b+1), J. Integer Sequences, 3 (2000), #P00.2.7.`
	EXAMPLE	`43 is in the sequence since (2^7+1)/(2+1)=129/3=43; indeed also (7^3+1)/(7+1)=344/8=43.`
	CROSSREFS	`Cf. A007583, A002061, A059055.` `Sequence in context: A129748 A078098 A154831 this_sequence A109492 A095286 A106561` `Adjacent sequences: A059051 A059052 A059053 this_sequence A059055 A059056 A059057`
	KEYWORD	`nonn`
	AUTHOR	`Henry Bottomley (se16(AT)btinternet.com), Dec 21 2000`

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Last modified December 3 22:15 EST 2009. Contains 170310 sequences.

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