

A097445


Second occurrence where n#  p is prime for primes p = 3, 5, ...


0



19, 197, 2293, 30011, 510463, 9699653, 223092809, 6469693163, 200560490051, 7420738134703, 304250263527157, 13082761331669881, 614889782588491313, 32589158477190044641, 1922760350154212638961, 117288381359406970983047
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OFFSET

2,1


COMMENTS

Care has to be taken to start with a large enough n to be sure terms are not missed. This was for n=100. This and A097444 were difficult to obtain using PARI.


LINKS



FORMULA

n# is n primorial = product of primes 2*3*5*...*p <= n.


EXAMPLE

3# = 2*3 = 6. 6  3 = 3 (first prime), 6  5 = 1, not prime, thus 3#  p is omitted.
5# = 2*3*5 = 30. 30  7 = 23 (first prime), 30  11 = 19 (second prime).


PROG

(PARI) primorm2(n) = { pr=1; for(x=1, n, f=1; pr*=prime(x); for(m=1, n, y=prprime(m); if(isprime(y), f=1; for(m=m+1, n, y=prprime(m); if(isprime(y), print1(y", "); f=0; break, f=1)); ); if(f==0, break) ) ) }


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



