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A161500
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Primes dividing some member of A073833.
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0
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2, 5, 29, 41, 89, 101, 109, 269, 421, 509, 521, 709, 929, 941, 1549, 1861, 2281, 2521, 2749, 2801, 2909, 3121, 3169, 3469, 5821, 5881, 7109, 8069, 8969, 9041, 9181, 10061, 10601, 11549, 15121, 16061, 16889, 16981, 21929, 30089, 30169, 32561, 41149
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Primes that divide A073833(n) will divide A073834(m) for any m > n, and this is all the prime divisors of A073834(m).
Iterating f(x) = x + 1/x modulo p will eventually either produce a zero (in which case p is in this sequence), or it will loop to an earlier term (in which case it is not). Since f(-x) = -f(x), encountering the negation of an earlier term means that the iteration is looping.
Note that A073833(6) = 969581 = 521 * 1861 is the first composite member of that sequence.
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PROG
| (PARI) ina(p)=local(m, k, v); m=Mod(1, p); v=vector(p\2); while(m!=0, k=lift(m); if(2*k>p, k=p-k); if(v[k], return(0)); v[k]=1; m+=1/m); 1
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CROSSREFS
| Cf. A073833, A073834, A000057.
Sequence in context: A098858 A134449 A103579 * A061351 A126107 A193901
Adjacent sequences: A161497 A161498 A161499 * A161501 A161502 A161503
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KEYWORD
| nonn
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AUTHOR
| Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Jun 11 2009
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