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A004153 Factorial numbers written backwards. 3
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 (list; graph; refs; listen; history; text; internal format)
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

P:=proc(i) local a, b, c, n; for n from 1 by 1 to i do a:=evalf(floor(log10(n!)+1)); b:=n!; c:=0; while a>0 do c:=c+(b-(trunc(b/10)*10))*10^(a-1); b:=trunc(b/10); a:=a-1; od; print(c); od; end: P(100) # Paolo P. Lava, Aug 07 2008

# second Maple program:

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.

Sequence in context: A319633 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

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Last modified February 26 04:47 EST 2020. Contains 332276 sequences. (Running on oeis4.)