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.

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A182685 a(n) = the smallest n-digit number with exactly 13 divisors, a(n) = 0 if no such number exists.

Original entry on oeis.org

0, 0, 0, 4096, 0, 531441, 0, 0, 244140625, 0, 13841287201, 0, 3138428376721, 23298085122481, 582622237229761, 2213314919066161, 21914624432020321, 353814783205469041, 6582952005840035281, 22563490300366186081
Offset: 1

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Author

Jaroslav Krizek, Nov 27 2010

Keywords

Comments

a(n) = the smallest n-digit number of the form p^12 (p = prime), a(n) = 0 if no such number exists.

Crossrefs

Cf. A030631, A182686.

Programs

  • Maple
    A055642 := proc(n) max(1,ilog10(n)+1) ; end proc:
A182685 := proc(n) for i from 1 do p := ithprime(i)^12 ; if A055642(p) > n then return 0 ; elif A055642(p) = n then return p; end if; end do: end proc:

Formula

A000005(a(n)) = 13.
a(n) = A182686(n) for n <= 17.
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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