OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..20000 (first 10000 terms from Chai Wah Wu)
FORMULA
a(0) = 0, a(10n+m) = a(n) + m*(n+1) for m in {0,...,9}. - Alois P. Heinz, Nov 20 2015
EXAMPLE
S_0 = [0], so a(0)=0,
...
S_9 = [0,1,2,3,4,5,6,7,8,9], so a(9) = 9,
S_10 = [0,01,1,2,3,4,5,6,7,8,9], so a(10) = 1,
S_11 = [0,01,1,11,2,3,4,5,6,7,8,9], so a(11) = 3,
...
S_20 = [0,01,02,1,11,2,21,3,31,4,41,5,51,6,61,7,71,8,81,9,91], so a(20) = 2, and so on
MAPLE
a:= proc(n) option remember; `if`(n=0, 0,
irem(n, 10, 'r')*(r+1)+a(r))
end:
seq(a(n), n=0..101); # Alois P. Heinz, Nov 20 2015
MATHEMATICA
A264600[0]=0; A264600[n_]:=A264600[n]=Mod[n, 10](Floor[n/10]+1)+A264600[Floor[n/10]]; Array[A264600, 100, 0] (* Paolo Xausa, Nov 04 2023, after Alois P. Heinz *)
PROG
(Python)
def A264600(n):
return sorted(str(i)[::-1] for i in range(n+1)).index(str(n)[::-1]) # Chai Wah Wu, Nov 20 2015
CROSSREFS
KEYWORD
nonn,base
AUTHOR
N. J. A. Sloane, Nov 20 2015
EXTENSIONS
More terms from Alois P. Heinz, Nov 20 2015
STATUS
approved