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A072999 a(n+1) is the smallest prime>a(n) such that a(n+1) == a(n-1) (mod a(n)). 7
2, 3, 5, 13, 31, 137, 853, 6961, 28697, 179143, 6836131, 68540453, 966402473, 15530980021, 94152282599, 203835545219, 2540178825227, 61168127350667, 6119352913891927, 220357873027460039, 16312601956945934813 (list; graph; refs; listen; history; internal format)
OFFSET

0,1

LINKS

T. D. Noe, Table of n, a(n) for n=0..100

EXAMPLE

After 3,5, one can't have composite 8, so keep adding 5 until you reach 13. After 5,13, one can't have composite 18, so keep adding 13 until you reach 31.

PROG

(PARI) l=2; h=3; print1("2, 3, "); while(l<2^128, t=l+h; while(!isprime(t), t+=h); print1(t, ", "); l=h; h=t)

CROSSREFS

Cf. A073680

Sequence in context: A041519 A060434 A175093 * A173268 A141179 A079147

Adjacent sequences:  A072996 A072997 A072998 * A073000 A073001 A073002

KEYWORD

nonn

AUTHOR

Phil Carmody (pc+oeis(AT)asdf.org), Aug 15 2002

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Last modified February 15 13:26 EST 2012. Contains 205802 sequences.