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Search: id:A097445
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| A097445 |
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Second occurrence where n# - p is prime for primes p = 3,5,... |
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+0
1
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| 19, 197, 2293, 30011, 510463, 9699653, 223092809, 6469693163, 200560490051, 7420738134703, 304250263527157, 13082761331669881, 614889782588491313, 32589158477190044641, 1922760350154212638961, 117288381359406970983047
(list; graph; listen)
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OFFSET
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2,1
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COMMENT
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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.
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FORMULA
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n# is n primorial = product of primes 2*3*5*...*p<=n
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EXAMPLE
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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.
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PROGRAM
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(PARI) primorm2(n) = { pr=1; for(x=1, n, f=1; pr*=prime(x); for(m=1, n, y=pr-prime(m); if(isprime(y), f=1; for(m=m+1, n, y=pr-prime(m); if(isprime(y), print1(y", "); f=0; break, f=1)); ); if(f==0, break) ) ) }
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CROSSREFS
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Sequence in context: A120791 A048556 A141995 this_sequence A058370 A066007 A135162
Adjacent sequences: A097442 A097443 A097444 this_sequence A097446 A097447 A097448
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KEYWORD
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nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Aug 23 2004
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