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A075713
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1+n+n^19 is a prime.
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1
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1, 8, 15, 20, 29, 33, 48, 98, 105, 114, 177, 231, 260, 302, 320, 338, 387, 393, 432, 456, 473, 488, 489, 558, 564, 632, 677, 680, 726, 770, 795, 828, 855, 869, 1019, 1026, 1050, 1056, 1079, 1119, 1124, 1217, 1266, 1302, 1373, 1454, 1467, 1547
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| For s = 5,8,11,14,17,20,..., n_s=1+n+n^s is always composite for any n>1. Also at n=1, n_s=3 is a prime for any s. So it is interesting to consider only the cases of s =/= 5,8,11,14,17,20,... and n>1. Here i consider the case s=19 and find several first n's making n_s a prime (or a probable prime).
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EXAMPLE
| 8 is OK because at s=19, n=8, n_s=1+n+n^s=144115188075855881 is a prime.
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PROG
| (PARI) for(n=1, 2000, if(isprime(1+n+n^19), print1(n", ")))
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CROSSREFS
| Cf. A002384, A075714.
Sequence in context: A014544 A122754 A082867 * A089025 A088977 A070043
Adjacent sequences: A075710 A075711 A075712 * A075714 A075715 A075716
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KEYWORD
| nonn
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AUTHOR
| Zak Seidov (zakseidov(AT)yahoo.com), Oct 03 2002
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EXTENSIONS
| More terms from Ralf Stephan (ralf(AT)ark.in-berlin.de), Mar 31 2003
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