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A247835 Numbers a(n) such that A247834(a(n)) = prime(n)^3, or a(n)=0 if prime(n)^3 is not in A247834. 3
1, 0, 3, 4, 7, 9, 13, 15, 21, 27, 29, 37 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Conjecture: all a(n)>0, except for n=2.

LINKS

Table of n, a(n) for n=1..12.

FORMULA

If prime(n)^3 is in A247834, then a(n) = pi(prime(n)^(3/2)) - n + 1, where pi(x) is the prime counting function (A000720).

EXAMPLE

Using the formula, let us find the position in A247834, in which should be 17^3, if 17^3 belongs to A247834. Since 17=prime(7), then we have a(7) = pi(17^(3/2)) - 6 = pi(70)-6 = 19-6=13. Indeed, A247834(13)=4913=17^3.

CROSSREFS

Cf. A030078, A156759, A247393, A247394, A247395, A247396, A247509, A247510, A247511, A247606, A247834, A247867.

Sequence in context: A203623 A053099 A073273 * A072441 A152032 A004652

Adjacent sequences:  A247832 A247833 A247834 * A247836 A247837 A247838

KEYWORD

nonn,more

AUTHOR

Vladimir Shevelev, Sep 24 2014

STATUS

approved

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Last modified November 19 16:06 EST 2019. Contains 329320 sequences. (Running on oeis4.)