id:A138758 - OEIS Search Results

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Index of A001203(n) (continued fraction for pi) in A000040 (primes), or 0 if A001203(n) is not prime.

+0
4

2, 4, 0, 0, 0, 0, 0, 0, 1, 0, 2, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 2, 6, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 2, 3, 0, 0, 0, 0, 0, 4, 0, 1, 2, 4, 0, 1, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 3, 1, 1, 2, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 2, 0, 1, 0, 0, 0, 1, 3, 0, 0, 1 (list; graph; listen)

	OFFSET	`1,1`
	FORMULA	`a(n) = A000720(A001203(n)) * A010051(A001203(n))`
	EXAMPLE	`This sequence starts 2,4,0,0,... since the 1st and 2nd terms of the continued fraction expansion of Pi, A001203 = (3, 7, 15, 1,...) are the 2nd resp. 4th primes, while the next two terms are not primes.`
	PROGRAM	`(PARI) default(realprecision, 1000); t=contfrac(Pi); vector(#t, i, isprime(t[i])*primepi(t[i]))`
	CROSSREFS	`Cf. A001203, A138757, A138759, A005042.` `Sequence in context: A139627 A166926 A028573 this_sequence A107501 A126732 A028586` `Adjacent sequences: A138755 A138756 A138757 this_sequence A138759 A138760 A138761`
	KEYWORD	`nonn`
	AUTHOR	`M. F. Hasler (www.univ-ag.fr/~mhasler), Mar 31 2008`

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Last modified December 13 23:45 EST 2009. Contains 170824 sequences.

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