OFFSET
0,4
COMMENTS
The function F was defined by Dan Asimov on the Mailing list Math-Fun on Aug. 18, 2024.
MAPLE
F:= S-> add(add((j-i-abs(S[j]-S[i]))^2, i=1..j-1), j=2..nops(S)):
a:= n-> nops({map(F, combinat[permute](n))[]}):
seq(a(n), n=0..10);
CROSSREFS
KEYWORD
nonn,more
AUTHOR
W. Edwin Clark, Aug 21 2024
EXTENSIONS
a(11)-a(13) from Hugo Pfoertner, Aug 24 2024
a(14)-a(15) from Hugo Pfoertner, Sep 04 2024
STATUS
approved