id:A131101 - OEIS Search Results

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Numbers that when added it to their prime factors +1 the result is a prime number, member of A131102.

+0
2

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; listen)

	OFFSET	`1,2`
	COMMENT	`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)`
	FORMULA	`a(n)+ prime factors of a(n) + 1 = p ; p is a prime number, member of A131102.`
	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).`
	CROSSREFS	`Adjacent sequences: A131098 A131099 A131100 this_sequence A131102 A131103 A131104` `Sequence in context: A073880 A118332 A118333 this_sequence A005384 A118571 A118504`
	KEYWORD	`easy,nonn`
	AUTHOR	`Tomas Xordan (xordan.tom(AT)gmail.com), Jun 14 2007`

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Last modified October 7 14:39 EDT 2008. Contains 144666 sequences.

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