login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A192010 The smallest number with n digits in its prime factorization (total count of digits of all bases and exponents). 2
1, 4, 12, 36, 132, 396, 1716, 5148, 25740, 87516, 437580, 1662804, 8314020, 38244492, 167943204, 839716020, 3862693692, 17298150012, 86490750060, 397857450276, 1850902051284, 9254510256420, 42570747179532, 201748323589956, 1008741617949780, 4640211442568988 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A050252(a(n)) = n and A050252(m) <> n for m < a(n);

LINKS

Table of n, a(n) for n=1..26.

EXAMPLE

a(2) = 4 = 2^2 and A050252(12) = (1+1) = 2;

a(3) = 12 = 2^2 * 3 and A050252(12) = (1+1) + 1 = 3;

a(4) = 36 = 2^2 * 3^2 and A050252(36) = (1+1) + (1+1) = 4;

a(5) = 132 = 2^2 * 3 * 11 and A050252(132) = (1+1) + 1 + 2 = 5;

a(6) = 396 = 2^2 * 3^2 * 11 and A050252(396) = (1+1) + (1+1) + 2 = 6;

a(7) = 1716 = 2^2 * 3 * 11 * 13 and A050252(1716) = (1+1) + 1 + 2 + 2 = 7;

a(8) = 5148 = 2^2 * 3^2 * 11 * 13 and A050252(5148) = (1+1) + (1+1) + 2 + 2 = 8;

a(9) = 25740 = 2^2 * 3^2 * 5 * 11 * 13 and A050252(25740) = (1+1) + (1+1) + 1 + 2 + 2 = 9;

a(10) = 87516 = 2^2 * 3^2 * 11 * 13 * 17 and A050252(87516) = (1+1) + (1+1) + 2 + 2 + 2 = 10;

a(11) = 437580 = 2^2 * 3^2 * 5 * 11 * 13 * 17 and A050252(437580) = (1+1) + (1+1) + 1 + 2 + 2 + 2 = 11;

a(12) = 1662804 = 2^2 * 3^2 * 11 * 13 * 17 * 19 and A050252(1662804) = (1+1) + (1+1) + 2 + 2 + 2 + 2 = 12;

a(13) = 8314020 = 2^2 * 3^2 * 5 * 11 * 13 * 17 * 19 and A050252(8314020) = (1+1) + (1+1) + 1 + 2 + 2 + 2 + 2 = 13.

PROG

(Haskell)

import Data.List (elemIndex)

import Data.Maybe (fromJust)

a192010 n = succ $ fromJust $ elemIndex n $ map a050252 [1..]

CROSSREFS

Sequence in context: A055395 A113990 A231179 * A252697 A056383 A293857

Adjacent sequences:  A192007 A192008 A192009 * A192011 A192012 A192013

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Jun 21 2011

EXTENSIONS

a(14)-a(26) from Donovan Johnson, Jul 03 2011

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 18 16:41 EDT 2019. Contains 322209 sequences. (Running on oeis4.)