id:A087128 - OEIS Search Results

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a(1)=1 and, for n>1, a(n) is the smallest positive integer such that 1+Sum[k, k=a(n-1)+1,...,a(n)] is prime.

+0
3

1, 2, 5, 6, 13, 22, 25, 34, 37, 46, 58, 61, 73, 97, 106, 142, 145, 178, 181, 193, 202, 205, 217, 226, 238, 253, 277, 286, 298, 313, 346, 358, 382, 385, 394, 430, 433, 442, 466, 502, 529, 541, 553, 562, 565, 586, 682, 685, 694, 697, 709, 718, 721, 733, 838, 841 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`It appears that, for n>4, all differences a(n+1)-a(n) are multiples of 3. The sequence of differences is A087129.`
	EXAMPLE	`a(2)=2 since 1+(2)=3 is prime. a(3)=5 since 1+(3+4+5)=13 is prime.`
	CROSSREFS	`Sequence in context: A028259 A027010 A038191 this_sequence A154365 A029544 A058668` `Adjacent sequences: A087125 A087126 A087127 this_sequence A087129 A087130 A087131`
	KEYWORD	`nonn`
	AUTHOR	`John W. Layman (layman(AT)math.vt.edu), Aug 16 2003`

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Last modified December 8 08:31 EST 2009. Contains 170430 sequences.

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