

A068596


Number of 4ary Lyndon words whose trace and subtrace are both 0 mod 4.


11



1, 0, 1, 1, 11, 44, 169, 588, 1948, 6560, 23133, 84565, 317755, 1198336, 4509419, 16909184, 63409935, 238609052, 902444517, 3429249843, 13076666409, 49977802752, 191312873561, 733365845820, 2815437297416, 10825960652800, 41694907460224, 160823207301705
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OFFSET

1,5


COMMENTS

The trace of a word is the sum of its characters; the subtrace of a word is the sum of all products of pairs of its characters.


LINKS

Table of n, a(n) for n=1..28.
Max Alekseyev, PARI/GP scripts for miscellaneous math problems
F. Ruskey, 4ary Lyndon words with given trace and subtrace


CROSSREFS

Cf. A074403, A074404, A074405, A074406, A074407, A074408, A074409, A074410, A074411, A074412, A074413.
Sequence in context: A299286 A022816 A120537 * A002089 A042521 A041228
Adjacent sequences: A068593 A068594 A068595 * A068597 A068598 A068599


KEYWORD

nonn


AUTHOR

Frank Ruskey, Mar 28 2002


EXTENSIONS

Terms a(15) onward from Max Alekseyev, Apr 09 2013


STATUS

approved



