A004153 Factorial numbers written backwards.

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

Alois P. Heinz, Table of n, a(n) for n = 0..500

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

Cf. A000142, A004086, A004192.

Sequence in context: A336281 A326268 A096138 * A071440 A280043 A309813

Adjacent sequences: A004150 A004151 A004152 * A004154 A004155 A004156

Keyword

nonn,base

Author

N. J. A. Sloane

Extensions

More terms from Eric M. Schmidt, Apr 04 2014

Status

approved