

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
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OFFSET

1,1


COMMENTS

a(n) is the largest prime < A079779(n).


LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000


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

Cf. A057855, A079779.
Sequence in context: A256491 A106009 A194552 * A178621 A309230 A048871
Adjacent sequences: A079777 A079778 A079779 * A079781 A079782 A079783


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



