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Search: id:A114951
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| A114951 |
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Numbers n such that the sum of the n-th triangular number and the n-th prime is prime. |
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+0
1
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| 1, 3, 4, 11, 15, 19, 20, 23, 24, 32, 39, 48, 51, 60, 67, 68, 71, 75, 83, 84, 88, 95, 100, 104, 111, 119, 120, 127, 132, 135, 143, 147, 168, 180, 183, 191, 195, 200, 203, 204, 207, 211, 212, 219, 236, 240, 243, 251, 252, 255, 275, 276, 284
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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The 11th triangular number is 66, the 11th prime is 31.
Their sum is 97, a prime. Therefore 11 is in the sequence.
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MATHEMATICA
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Select[Range[500], PrimeQ[ #*(# + 1)/2 + Prime[ # ]] &]
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CROSSREFS
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Cf. A000217.
Sequence in context: A075646 A133621 A049619 this_sequence A085368 A041405 A042483
Adjacent sequences: A114948 A114949 A114950 this_sequence A114952 A114953 A114954
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KEYWORD
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nonn,less
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AUTHOR
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J. M. Bergot (thekingfishb(AT)yahoo.ca), Jun 23 2007
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EXTENSIONS
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Edited and extended by Stefan Steinerberger (stefan.steinerberger(AT)gmail.com) and Robert G. Wilson v (rgwv@rgwv.com), Jun 24 2007
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