A004719 Delete all 0's from n.

1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 11, 12, 13, 14, 15, 16, 17, 18, 19, 2, 21, 22, 23, 24, 25, 26, 27, 28, 29, 3, 31, 32, 33, 34, 35, 36, 37, 38, 39, 4, 41, 42, 43, 44, 45, 46, 47, 48, 49, 5, 51, 52, 53, 54, 55, 56, 57, 58, 59, 6, 61, 62, 63, 64, 65, 66, 67, 68, 69, 7, 71, 72, 73, 74, 75, 76, 77, 78, 79, 8, 81, 82, 83, 84, 85, 86, 87, 88, 89, 9, 91, 92, 93, 94, 95, 96, 97, 98, 99, 1, 11, 12, 13, 14, 15, 16, 17, 18, 19, 11, 111, 112, 113, 114, 115, 116, 117, 118, 119, 12

Offset: 1

Author

N. J. A. Sloane

Keywords

• base
• nonn
• look

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A004151.

Programs

Haskell

a004719 = read . filter (/= '0') . show :: Integer -> Integer
-- Reinhard Zumkeller, Feb 02 2012

Maple

noz:=proc(n) local a,t1,i,j; a:=0; t1:=convert(n,base,10); for i from 1 to nops(t1) do j:=t1[nops(t1)+1-i]; if j <> 0 then a := 10*a+j; fi; od: a; end;
[seq(f(n),n=1..200)]; # N. J. A. Sloane, Jun 11 2014

Mathematica

Table[FromDigits[DeleteCases[IntegerDigits[n], 0]], {n, 120}] (* Alonso del Arte, Nov 10 2018 *)

PARI

a(n, base=10) = fromdigits(select(sign, digits(n, base)), base) \\ Rémy Sigrist, Nov 10 2018

Python

def A004719(n): return int(str(n).replace('0','')) # Chai Wah Wu, Feb 20 2024

Formula

a(n) = if n <= 9 then n else (if n mod 10 = 0 then a(n/10) else 10*a(floor(n/10)) + n mod 10). [Reinhard Zumkeller, Feb 02 2012]