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Search: id:A119613
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| A119613 |
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Numbers n such that the difference between the largest distinct prime divisor and the smallest distinct prime divisor is a prime. |
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+0
2
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| 10, 14, 15, 20, 26, 28, 30, 35, 38, 40, 42, 45, 50, 52, 56, 60, 62, 70, 75, 76, 78, 80, 84, 86, 90, 98, 100, 104, 112, 114, 120, 122, 124, 126, 130, 135, 140, 143, 146, 150, 152, 156, 160, 168, 172, 175, 180, 182, 186, 190, 196, 200, 206, 208, 210, 218, 224, 225
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OFFSET
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1,1
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EXAMPLE
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If n = 10 then the prime divisors are 2 and 5, and the difference between these two is 3 which is also a prime. So 10 is in the sequence.
If n = 70 then the prime divisors are 2, 5 and 7, and the difference between the largest and the smallest distinct prime divisors is 5 which is also a prime. So 70 is in the sequence.
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MATHEMATICA
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Select[Range[2, 300], Not[Length[FactorInteger[ # ]]==1]&&PrimeQ[FactorInteger[ # ][[ -1, 1]] -FactorInteger[ # ][[1, 1]]] &] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Jun 06 2006
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CROSSREFS
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Sequence in context: A102361 A121836 A081062 this_sequence A036338 A108793 A100929
Adjacent sequences: A119610 A119611 A119612 this_sequence A119614 A119615 A119616
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KEYWORD
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nonn,less
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AUTHOR
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Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Jun 05 2006
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EXTENSIONS
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Corrected and extended by Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Jun 06 2006
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