id:A068638 - OEIS Search Results

Search: id:A068638

Displaying 1-1 of 1 results found.

page 1

a(1) =1, a(n) = smallest composite number such that a(n) + a(k) is a composite number for all k = 1 to n.

+0
3

1, 8, 14, 20, 24, 25, 26, 32, 38, 44, 50, 56, 62, 68, 74, 80, 86, 90, 92, 94, 98, 104, 110, 116, 118, 120, 122, 128, 134, 140, 144, 146, 152, 158, 160, 164, 170, 176, 182, 184, 188, 194, 200, 206, 212, 218, 220, 224, 230, 234, 236, 242, 248, 254, 260, 264, 266 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`Conjecture: 25 is the largest odd term of this sequence.`
	EXAMPLE	`a(2) = 8 as for the smaller composite numbers 4 and 6 one gets 4+1 =5 and 6 +1 = 7 both primes. a(3) = 14 as 1 +14 = 15 and 8 +14 =22 are composite.`
	CROSSREFS	`Sequence in context: A096229 A112277 A078754 this_sequence A025044 A125163 A063288` `Adjacent sequences: A068635 A068636 A068637 this_sequence A068639 A068640 A068641`
	KEYWORD	`base,easy,nonn`
	AUTHOR	`Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Feb 27 2002`
	EXTENSIONS	`More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Mar 17 2002`

page 1

Search completed in 0.002 seconds

Last modified July 26 13:41 EDT 2008. Contains 142293 sequences.

AT&T Labs Research