A110394 a(1) = 1; a(n) = n times (9's complement of a(n-1)).

1, 16, 249, 3000, 34995, 390024, 4269825, 45841392, 487427463, 5125725360, 53617021029, 556595747640, 5764255280667, 59300426070648, 610493608940265, 6232102256955744, 64054261631752335, 647023290628457952

Offset: 1

Author

Amarnath Murthy, Jul 29 2005

Keywords

• base
• easy
• nonn

Comments

a(1)=1; a(n)=n*[99...9 - a(n-1)] for n>1 (99...9 and a[n-1] have the same number of digits). - Emeric Deutsch, Jul 31 2005

Examples

			a(4) = 4 times 9's complement of a(3) = 4*(999-249) = 3000.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..400

Programs

Maple

s:=proc(m) nops(convert(m,base,10)) end: a[1]:=1: for n from 2 to 21 do a[n]:=n*(10^s(a[n-1])-1-a[n-1]) od: seq(a[n],n=1..21); # Emeric Deutsch, Jul 31 2005
# second Maple program:
a:= proc(n) option remember; `if`(n=1, 1,
       n*(p-> 10^length(p)-1-p)(a(n-1)))
    end:
seq(a(n), n=1..30);  # Alois P. Heinz, Sep 22 2015

Mathematica

nxt[{n_,a_}]:={n+1,(n+1)(FromDigits[PadRight[{},IntegerLength[a],9]]-a)}; NestList[nxt,{1,1},20][[;;,2]] (* Harvey P. Dale, Mar 13 2024 *)

Extensions

More terms from Emeric Deutsch, Jul 31 2005