|
Search: id:A135206
|
|
|
| A135206 |
|
Numbers n for which Sum_digits(n!) is a multiple of Sum_digits(n!!). |
|
+0
3
|
|
| 1, 2, 3, 11, 19, 28, 48, 64, 158, 164, 190, 308, 324
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
EXAMPLE
|
11!=11*10*9*8*7*6*5*4*3*2*1=39916800 -> (3+9+9+1+6+8+0+0)=36
11!!=11*9*7*5*3*1=10395 -> (1+0+3+9+5)=18
36/18=2
|
|
MAPLE
|
P:=proc(n) local i, j, k, w, x; for i from 1 by 1 to n do w:=0; k:=i!; while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; x:=i; j:=i-2; while j >0 do x:=x*j; j:=j-2; od: k:=x; x:=0; while k>0 do x:=x+k-(trunc(k/10)*10); k:=trunc(k/10); od; if trunc(w/x)=w/x then print(i); fi; od; end: P(1000);
|
|
CROSSREFS
|
Cf. A004152, A120390, A108825, A129980, A131954, A131955, A135204, A135205.
Sequence in context: A025101 A025105 A095984 this_sequence A111802 A095282 A051071
Adjacent sequences: A135203 A135204 A135205 this_sequence A135207 A135208 A135209
|
|
KEYWORD
|
hard,nonn,base
|
|
AUTHOR
|
Paolo P. Lava (ppl(AT)spl.at), Nov 30 2007
|
|
|
Search completed in 0.002 seconds
|
