

A336433


Number of sequences of n numbers from 1 to n that do not have a subsequence that adds up to n.


1



0, 0, 0, 1, 5, 68, 403, 7257, 61686, 1174434, 13810620, 335547727, 3783688286, 124486381056, 1935430229612, 55798127869680, 1058567311736669, 39819079382937334, 717447490866241055, 32064848897165970340, 666062878027691348450, 28916070816360797805534
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OFFSET

0,5


COMMENTS

The sequence is bounded above for odd n by (((n1)/2)^n)*(2^((n1)/2)).
Growth appears to be slightly faster than exponential, but irregular, with oddnumbered terms larger than the trend.


LINKS

Christopher L. Reedy, Table of n, a(n) for n = 1..30
Pierre Abbat, Fullproc
Christopher L. Reedy, sequence.py


EXAMPLE

For n=3, the only solution is 2,2,2.
For n=4, the 5 solutions are 3,3,3,3 and the four permutations of 3,3,3,2.


PROG

(C++) See Fullproc link.
(Python) See sequence.py link.


CROSSREFS

Cf. A000312.
Sequence in context: A252794 A328359 A003361 * A099334 A281558 A165396
Adjacent sequences: A336427 A336428 A336429 * A336434 A336436 A336437


KEYWORD

nonn


AUTHOR

Pierre Abbat, Jul 21 2020


EXTENSIONS

a(19)a(21) from Christopher L. Reedy, Aug 06 2020


STATUS

approved



