A082132 a(0) = 5; for n > 0, a(n) is the greatest prime factor of PP(a(n-1))*a(n-1)-2 where PP(n) is an abbreviation for PreviousPrime(n).

5, 13, 47, 673, 1093, 4789, 15887, 6961, 7079, 1853387, 5636791, 16319158451, 46975091221, 97536826417, 9513432505744326182381, 2335222008886384800739, 7440517660385876970522347503153, 83914607657246408236765553419, 1960358081272210906656999086971746456168551

Offset

0,1

Comments

Some of the larger entries may only correspond to probable primes.

Links

Tyler Busby, Table of n, a(n) for n = 0..22

Prog

(PARI) p=5; for(k=1, 20, print1(p, ", "); p=precprime(p-1)*p-2; f=factor(p); s=matsize(f)[1]; p=f[s, 1]) \\ Rick L. Shepherd, Dec 19 2004

Crossrefs

Cf. A082021, A031441, A031442.

Sequence in context: A250133 A025545 A146152 * A220900 A138277 A343549

Adjacent sequences: A082129 A082130 A082131 * A082133 A082134 A082135

Keyword

nonn

Author

Yasutoshi Kohmoto, May 10 2003

Extensions

Edited by Rick L. Shepherd, Dec 19 2004

a(18) from Tyler Busby, Oct 22 2023

Status

approved