id:A087372 - OEIS Search Results

Search: id:A087372

Displaying 1-1 of 1 results found.

page 1

Smallest k such that 3^k + 2n is a prime, or 0 if no such k exists. Index of the smallest power of 3 which when increased by the n-th even number yields a prime.

+0
1

1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 2, 0, 1, 1, 0, 2, 1, 0, 1, 1, 0, 1, 3, 0, 1, 2, 0, 1, 1, 0, 2, 1, 0, 1, 1, 0, 2, 1, 0, 1, 3, 0, 1, 2, 0, 2, 1, 0, 1, 1, 0, 1, 1, 0, 1, 3, 0, 4, 2, 0, 2, 1, 0, 1, 2, 0, 1, 1, 0, 2, 2, 0, 1, 1, 0, 3, 1, 0, 2, 1, 0, 1, 3, 0, 1, 2, 0, 1, 1, 0, 2, 2, 0, 1, 1, 0, 1, 1, 0, 3, 2, 0, 3, 1, 0 (list; graph; listen)

	OFFSET	`1,11`
	COMMENT	`Most of the terms are 0, 1 or 2. Subsidiary sequence: Index of the first occurrence of n. Conjecture: There exists a finite M such that a(n) < M for all n.`
	EXAMPLE	`a(10) = 1 as 3^1 + 20 = 23 is a prime.` `a(23) = 3 as 3^3 +46 = 73 is a prime but 46+3 and 46+9 are not.`
	CROSSREFS	`Cf. A087371.` `Adjacent sequences: A087369 A087370 A087371 this_sequence A087373 A087374 A087375` `Sequence in context: A086966 A140080 A065359 this_sequence A036431 A029407 A099544`
	KEYWORD	`nonn`
	AUTHOR	`Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Sep 09 2003`
	EXTENSIONS	`More terms from David Wasserman (wasserma(AT)spawar.navy.mil), May 24 2005`

page 1

Search completed in 0.002 seconds

Last modified October 10 20:39 EDT 2008. Contains 144831 sequences.

AT&T Labs Research