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Search: id:A118624
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| A118624 |
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Let p(n) be the nth-prime. Sequence gives primes of the form | p(n)*p(n+2) - p(n+1)*p(n+3)| -1. |
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+0
1
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| 59, 359, 197, 719, 449, 971, 1019, 937, 419, 863, 809, 2203, 1979, 1693, 743, 2693, 3169, 1823, 3119, 1637, 2239, 4547, 4241, 4967, 4877, 4259, 2609, 5651, 7759, 7823, 4219, 8971, 6863, 6983, 7451, 3989, 12161, 8147, 11423, 10369, 9059, 3299, 6863
(list; graph; listen)
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OFFSET
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0,1
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FORMULA
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a(n) = | p(n)*p(n+2) - p(n+1)*p(n+3) | -1
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EXAMPLE
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11, 13, 17, 19 -> | 11*17-13*19 | - 1 = 59
23, 29, 31, 37 -> | 23*31-29*37 | - 1 = 359
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MAPLE
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P:=proc(n)local i, j; for i from 1 by 1 to n do j:=abs(ithprime(i)*ithprime(i+2)-ithprime(i+1)*ithprime(i+3))-1; if isprime(j) then print(j); fi; od; end: P(1000);
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CROSSREFS
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Cf. A117854.
Sequence in context: A142922 A033238 A142265 this_sequence A142604 A071771 A125034
Adjacent sequences: A118621 A118622 A118623 this_sequence A118625 A118626 A118627
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KEYWORD
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easy,nonn
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AUTHOR
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Paolo P. Lava and Giorgio Balzarotti (ppl(AT)spl.at), May 09 2006
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