id:A103790 - OEIS Search Results

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a(n) = the minimum k that makes prime(n)+A019565(k) prime.

+0
3

0, 1, 1, 3, 1, 3, 1, 5, 3, 1, 3, 3, 1, 5, 3, 3, 1, 3, 3, 1, 3, 5, 3, 9, 3, 1, 3, 1, 7, 9, 5, 3, 1, 5, 1, 3, 3, 5, 3, 3, 1, 5, 1, 3, 1, 7, 7, 3, 1, 5, 3, 1, 5, 3, 3, 3, 1, 3, 3, 1, 5, 9, 3, 1, 13, 7, 3, 5, 1, 5, 3, 7, 3, 3, 5, 3, 7, 11, 7, 5, 1, 5, 1, 3, 5, 3, 7, 3, 1, 15, 11, 7, 13, 7, 5, 3, 9, 1, 13, 3, 5, 3, 3 (list; graph; listen)

	OFFSET	`1,4`
	COMMENT	`All elements except the first one are odd. This suggests a new way looking for large primes candidates.`
	EXAMPLE	`Prime(1)+A019565(0)=2+1=3 is prime, so a(1)=0;` `Prime(4)+A019565(3)=7+6=13 is prime, so a(4)=3;`
	MATHEMATICA	`A019565 = Function[tn, k1 = tn; o = 1; tt = 1; While[k1 > 0, k2 = Mod[k1, 2]; If[k2 == 1, tt = tt*Prime[o]]; k1 = (k1 - k2)/2; o = o + 1]; tt]; Do[npd = Prime[n]; ts = 1; tt = ts; cp = npd + A019565[tt]; While[ ! (PrimeQ[cp]), ts = ts + 1; tt = ts; cp = npd + A019565[ tt]]; Print[ts], {n, 3, 200} ]`
	CROSSREFS	`Cf. A019565.` `Sequence in context: A095660 A035648 A053575 this_sequence A013603 A157892 A146907` `Adjacent sequences: A103787 A103788 A103789 this_sequence A103791 A103792 A103793`
	KEYWORD	`easy,nonn`
	AUTHOR	`Lei Zhou (lzhou5(AT)emory.edu), Feb 16 2005`

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Last modified November 27 14:46 EST 2009. Contains 167570 sequences.

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