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A028308 Form a triangle with n numbers in top row; all other numbers are the product of their parents. The numbers must be positive and distinct and the final number is to be minimized. 0
1, 6, 48, 4320, 46448640, 10835538739200000, 2672817951712314077919313920000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The next term has 69 digits. - Charlie Neder, Mar 09 2019

LINKS

Table of n, a(n) for n=1..7.

Problem 401 here suggested this sequence

EXAMPLE

Solutions for n=1,2,... are 1; 2 3; 3 2 4; 4 2 3 5; 5 3 2 4 7

Example triangle for a(4):

   4    2    3    5

     8    6    15

       48    90

         4320

Some solutions for a(6) and a(7) are (7,4,3,2,5,8) and (9,7,4,2,3,5,10), and others can be created by interchanging opposite numbers (e.g., swapping 5 and 7 in the second set). - Charlie Neder, Mar 09 2019

CROSSREFS

A less interesting cousin of A028307.

Sequence in context: A192769 A324461 A084259 * A173011 A061429 A048357

Adjacent sequences:  A028305 A028306 A028307 * A028309 A028310 A028311

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

a(7) and example removed from title by Charlie Neder, Mar 09 2019

STATUS

approved

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Last modified August 5 19:08 EDT 2021. Contains 346488 sequences. (Running on oeis4.)