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A004153
Factorial numbers written backwards.
4
1, 1, 2, 6, 42, 21, 27, 405, 2304, 88263, 88263, 861993, 6100974, 80207226, 219287178, 8634767031, 88898722902, 690824786553, 8275073732046, 238804001546121, 466718002092342, 4490717124909015, 867067777270004211, 4667948883761025852, 63934932337104844026
OFFSET
0,3
LINKS
FORMULA
a(n) = A004086(A000142(n)). - Michel Marcus, Apr 05 2014
MAPLE
a:= n-> (s-> parse(cat(s[-i]$i=1..length(s))))(""||(n!)):
seq(a(n), n=0..30); # Alois P. Heinz, Apr 09 2015
PROG
(PARI) reverse(expr)=my(v=Vec(Str(expr)), n=length(v)); eval(concat(vector(n, i, v[n-i+1])));
a(n) = reverse(n!); \\ Michel Marcus, Apr 05 2014
CROSSREFS
KEYWORD
nonn,base
EXTENSIONS
More terms from Eric M. Schmidt, Apr 04 2014
STATUS
approved