Smarandache-Wellin primes

N. J. A. Sloane njas at research.att.com
Sun Jan 18 19:37:26 CET 2004


There is a conflict between the Crandall-Pomerance book and the OEIS.
Would someone please check?   

The book says the concatenation of the first 719 primes is a prime.
This is the number  235711...5441 (since the 719-th prime is 5441).

Yet in the OEIS we have:

%S A019518 2,23,235,2357,235711,23571113,2357111317,235711131719,23571113171923,
%T A019518 2357111317192329,235711131719232931,23571113171923293137,
%U A019518 2357111317192329313741,235711131719232931374143,23571113171923293137414347
%N A019518 Smarandache-Wellin numbers: a(n) = concatenation of first n primes.
(fine)

%I A069151
%S A069151 2,23,2357
%N A069151 Concatenations of consecutive primes, starting with 2, that are also prime.
%C A069151 Prime Smarandacher-Wellin numbers.
...
%E A069151 The next term has 355 digits and is too large to include.
(presumably fine, but I did not check "355")

%S A046035 1,2,4,128,174,342,435,1429
%N A046035 Concatenation of first n primes is prime.
...
%A A046035 Eric W. Weisstein (eric(AT)weisstein.com)
%E A046035 Additional comments from Robert G. Wilson v (rgwv(AT)rgwv.com), Sep 10 2001
(surely 719 should be there?)

%S A046284 2,3,7,719,1033,2297,3037,11927
%N A046284 Concatenation of primes from 2 through p is a prime.
...
%A A046284 Patrick De Geest (pdg(AT)worldofnumbers.com), Jun 15 1998.
%E A046284 Additional comments from Robert G. Wilson v (rgwv(AT)rgwv.com), Sep 10 2001
(surely 5441 should be there?)

OTOH the book may be wrong and the OEIS entries correct.  Can someone check?

NJAS





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