OFFSET
1,2
COMMENTS
a(n) = n iff n < 10 OR n is a "9ish number": a(A011539(n)) = A011539(n). - Reinhard Zumkeller, Dec 29 2011
LINKS
R. Zumkeller, Table of n, a(n) for n = 1..11000
EXAMPLE
a(20)=2*3^1+0*1=6, a(21)=2*3^1+1*1=7, a(22)=2*3^1+2*1=8,
a(23)=2*4^1+3*1=11, a(24)=2*5^1+4*1=14, a(25)=2*6^1+5*1=17,
a(26)=2*7^1+6*1=20, a(27)=2*8^1+7*1=23, a(28)=2*9^1+8*1=26,
a(29)=2*10^1+9*1=29, a(30)=3*4^1+0*1=12, a(31)=3*4^1+1*1=13.
MAPLE
f:= proc(n) local b, L, i;
L:= convert(n, base, 10);
b:= max(L);
add(L[i]*(b+1)^(i-1), i=1..nops(L));
end proc:
map(f, [$1..100]); # Robert Israel, Feb 02 2016
MATHEMATICA
a[n_] := (id = IntegerDigits[n] // Reverse; b = Max[id]+1; id.b^Range[0, Length[id]-1]); Table[a[n], {n, 1, 75}] (* Jean-François Alcover, May 15 2013 *)
Table[FromDigits[IntegerDigits[n], Max[IntegerDigits[n]+1]], {n, 80}] (* Harvey P. Dale, Dec 02 2015 *)
PROG
(Haskell)
a068505 n = foldr (\d v -> v * b + d) 0 dds where
b = maximum dds + 1
dds = a031298_row n
-- Reinhard Zumkeller, Feb 17 2013, Dec 29 2011
(PARI) a(n)=my(d = digits(n), b = vecmax(d)); subst(Pol(d), x, b+1); \\ Michel Marcus, Feb 12 2016
CROSSREFS
KEYWORD
AUTHOR
Reinhard Zumkeller, Mar 11 2002, Feb 23 2008
EXTENSIONS
Definition clarified and comment corrected by Martin Büttner, Feb 02 2016
STATUS
approved