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A200997
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Terms of A135506 sorted (after removing the 1's).
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0
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2, 2, 5, 5, 5, 5, 7, 11, 11, 11, 13, 13, 13, 13, 13, 13, 13, 13, 17, 17, 17, 19, 23, 23, 23, 23, 23, 29, 29, 29, 29, 29, 31, 37, 41, 41, 41, 43, 43, 43, 43, 43, 47, 47, 47, 47, 47, 53, 53, 53, 59, 59, 59, 59, 59, 61, 61, 61, 61, 61, 61, 61, 67, 67, 67, 67, 67, 71, 71, 71, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 79, 83, 83, 83, 89
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OFFSET
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1,1
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COMMENTS
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Terms of the sequence are primes and all primes except 3 appear finitely many times. p>=5 occurs 1 time iff 2p-1 is prime (cf. A005382). p>=11 occurs 3 times iff 4p-1 is prime (cf. A062737). In general p occurs 2m-1 times iff 2mp-1 is prime and 2ip-1 is composite for i=1,2,3,...,m-1.
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LINKS
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PROG
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(PARI) v=[]; u1=1; for(n=2, 1000, u2=u1+lcm(n, u1); r=u1; u1=u2; if(u2/r-1>1, v=concat(v, [u2/r-1]); )); w=vecsort(v); a(n)=w[n];
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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