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A131101
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Numbers that when added it to their prime factors +1 the result is a prime number, member of A131102.
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1
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1, 2, 3, 5, 11, 23, 27, 29, 30, 32, 36, 41, 53, 60, 66, 75, 78, 83, 89, 113, 114, 117, 130, 131, 132, 138, 140, 171, 173, 175, 179, 186, 191, 204, 220, 233, 239, 240, 246, 251, 255, 258, 260, 276, 279, 281, 285, 286, 293, 308, 310, 325, 338, 340, 354, 359, 363
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| The Sophie Germain prime numbers (A005384) they are part of this sequence because when add to one of this its only prime factor (itself) + 1 = 2*A005384 + 1 the result are another prime number (A005385)
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FORMULA
| a(n)+ prime factors of a(n) + 1 = p ; p is a prime number, member of A131102.
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EXAMPLE
| a(8)=29 because 29 + its only prime factor (itself) + 1 = 29+29+1= 59, 59 are a prime number = A131102(8)=A005385(6) ; a(9)=30 becasue 30 + its prime factors + 1 = 30 +(2+3+5)+1 =41, 41 are a prime number = A131102(9).
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CROSSREFS
| Sequence in context: A073880 A118332 A118333 * A188534 A005384 A118571
Adjacent sequences: A131098 A131099 A131100 * A131102 A131103 A131104
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KEYWORD
| easy,nonn
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AUTHOR
| Tomas Xordan (xordan.tom(AT)gmail.com), Jun 14 2007
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