cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A131931 Smallest number containing exactly n prime factors in its decimal representation.

Original entry on oeis.org

1, 2, 132, 735, 21372, 271362, 4773132, 113678565, 11317129824
Offset: 0

Views

Author

Reinhard Zumkeller, Jul 30 2007

Keywords

Comments

A131929(a(n)) = n and A131929(m) <> n for m

Examples

			a(2) = 2^2 * 3 * 11 = 132 containing 2 and 3;
a(3) = 3 * 5 * 7^2 = 735 containing 3, 5 and 7;
a(4) = 2^2 * 3 * 13 * 137 = 21372 containing 2, 3, 13 and 137;
a(5) = 2 * 3 * 7^2 * 13 * 71 = 271362 containing 2, 3, 7, 13 and 71.

Crossrefs

Cf. A131930, A131929, A318965.

Extensions

Offset changed by and a(6)-a(8) from Giovanni Resta, Sep 06 2018

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