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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
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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; refs; listen; history; internal format)
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OFFSET
| 1,2
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EXAMPLE
| 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
| Select[Range[500], PrimeQ[ #*(# + 1)/2 + Prime[ # ]] &]
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CROSSREFS
| Cf. A000217.
Sequence in context: A075646 A133621 A049619 * A085368 A041405 A042483
Adjacent sequences: A114948 A114949 A114950 * A114952 A114953 A114954
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KEYWORD
| nonn,less
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AUTHOR
| J. M. Bergot (thekingfishb(AT)yahoo.ca), Jun 23 2007
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EXTENSIONS
| Edited and extended by Stefan Steinerberger (stefan.steinerberger(AT)gmail.com) and Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 24 2007
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