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A079780
a(n) = largest prime <= n*prime(n).
2
2, 5, 13, 23, 53, 73, 113, 151, 199, 283, 337, 443, 523, 601, 701, 839, 997, 1097, 1259, 1409, 1531, 1733, 1907, 2131, 2423, 2621, 2777, 2971, 3137, 3389, 3931, 4177, 4519, 4723, 5209, 5431, 5807, 6173, 6491, 6917, 7333, 7591, 8209, 8467, 8863, 9151, 9907
OFFSET
1,1
COMMENTS
a(n) is the largest prime < A079779(n).
LINKS
FORMULA
a(n) = prime(A057855(n)). - Michel Marcus, Aug 30 2019
MAPLE
With exception of first term: seq(prevprime(n*ithprime(n)), n=2..40);
MATHEMATICA
PrevPrim[n_] := Block[{k = n - 1}, While[ !PrimeQ[k], k-- ]; k]; Table[ Abs[ PrevPrim[ n*Prime[n]]], {n, 1, 50}]
Table[Abs[NextPrime[n Prime[n], -1]], {n, 50}] (* Harvey P. Dale, May 25 2012 *)
PROG
(PARI) for(n=1, 47, print1(precprime(n*prime(n)), ", "))
CROSSREFS
Sequence in context: A256491 A106009 A194552 * A178621 A362105 A309230
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Feb 03 2003
EXTENSIONS
Edited and extended by Robert G. Wilson v, Klaus Brockhaus and Mark Hudson (mrmarkhudson(AT)hotmail.com), Feb 04 2003
STATUS
approved