A138301 - OEIS

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A138301

Number of integers k < 10^n such that k*(k+1)-1 and k*(k+3)-1 are both first of twin primes.

1, 2, 4, 11, 37, 145, 673, 3748, 22875 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	EXAMPLE	`34-1=11 11 and 13 twin primes, 36-1=17 17 and 19 twin primes a(1)=1` `1516-1=239 239 and 241 twin primes, 1518-1=269 269 and 271 twin primes a(2)=2`
	CROSSREFS	`Cf. A138303.` `Sequence in context: A086611 A035098 A174107 * A173939 A118182 A179327` `Adjacent sequences: A138298 A138299 A138300 * A138302 A138303 A138304`
	KEYWORD	`nonn`
	AUTHOR	`Pierre CAMI (pierre-cami(AT)bbox.fr), Mar 14 2008`

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Last modified February 17 08:39 EST 2012. Contains 205998 sequences.