A221794 - OEIS

A221794

Number of primes of the form (x+1)^3 - x^3 with x <= 10^n.

1, 7, 42, 263, 1965, 15282, 126826

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OFFSET

0,2

COMMENTS

Cuban primes are primes that are the difference of two consecutive cubes, p = (x+1)^3 - x^3 (A002407). They are also primes of the form 3k(k+1) + 1, where values for k+1 are in A002504.

LINKS

Table of n, a(n) for n=0..6.

Ed Pegg, Jr., MathWorld: Cuban Prime

Wikipedia, Cuban prime

CROSSREFS

Cf. A002407, A002504, A003215, A113478 (number of cuban primes < 10^n).

Sequence in context: A127016 A152239 A152240 * A187246 A278152 A366222

Adjacent sequences: A221791 A221792 A221793 * A221795 A221796 A221797

KEYWORD

nonn

AUTHOR

Vladimir Pletser, Jan 25 2013

STATUS

approved