A007014 Largest prime <= Product prime(k).

2, 5, 29, 199, 2309, 30029, 510481, 9699667, 223092827, 6469693189, 200560490057, 7420738134751, 304250263527209, 13082761331669941, 614889782588491343, 32589158477190044657, 1922760350154212638963, 117288381359406970983181, 7858321551080267055878989

Offset: 1

Author

N. J. A. Sloane, Mira Bernstein, Robert G. Wilson v

Keywords

• nonn

Comments

A057705 contains terms of a(n) such that A002110(n) - a(n) = 1. -Michael De Vlieger, May 15 2017

Examples

			From _Michael De Vlieger_, May 15 2017: (Start)
a(1) = 2 since A002110(1) = 2. 2 is prime thus the largest prime <= 2 = 2.
a(2) = 5 since A002110(2) = 6. 5 is the largest prime <= 6. (End)
		

References

• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..350
• R. G. Wilson, V, Letter to N. J. A. Sloane, Jan. 1994

Crossrefs

Cf. A000849, A002110, A038710, A057705, A151799.

Programs

Mathematica

Array[Abs@ NextPrime[Product[Prime@ i, {i, #}], -1] &, 14] (* Michael De Vlieger, May 15 2017 *)

PARI

lista(n) = {prd = 1; for (i=1, n, prd *= prime(i); print1(precprime(prd), ", "););} \\ Michel Marcus, Jun 17 2013

PARI

a(n)=precprime(prod(i=1,n,prime(i))) \\ Charles R Greathouse IV, Jun 17 2013

Formula

From Michael De Vlieger, May 15 2017: (Start)

a(n) = prime(A000849(n)).

a(n) = A151799(A002110(n)). (End)

Extensions

Corrected by Jud McCranie, Jan 03 2001

More terms from Michael De Vlieger, May 15 2017