A080719 Replace decimal digits with their binary values and convert back to decimal representation.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 2, 3, 6, 7, 12, 13, 14, 15, 24, 25, 4, 5, 10, 11, 20, 21, 22, 23, 40, 41, 6, 7, 14, 15, 28, 29, 30, 31, 56, 57, 8, 9, 18, 19, 36, 37, 38, 39, 72, 73, 10, 11, 22, 23, 44, 45, 46, 47, 88, 89, 12, 13, 26, 27, 52, 53, 54, 55, 104, 105, 14, 15, 30, 31, 60, 61, 62

Offset: 0

Author

Reinhard Zumkeller, Mar 06 2003

Keywords

• nonn
• base

Comments

m is a local maximum iff m == 9 modulo 10 (see A017377).

A257831 seen as binary numbers: A007088(a(n)) = A257831(n). - Reinhard Zumkeller, May 10 2015

Examples

			n=27 -> '2''7' -> '10''111' -> '10111' -> 23: a(27)=23.
See also A257831.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A007088.

Cf. A257831, A030308, A031298.

Programs

Haskell

import Data.Maybe (mapMaybe)
a080719 = foldr (\b v -> 2 * v + b) 0 .
           concat . mapMaybe (flip lookup bin) . a031298_row
            where bin = zip [0..9] a030308_tabf
-- Reinhard Zumkeller, May 10 2015

Mathematica

Table[FromDigits[Flatten[IntegerDigits[#,2]&/@IntegerDigits[n]],2],{n,80}] (* Harvey P. Dale, Aug 30 2014 *)

Python

def A080719(n):
    return int(''.join((format(int(d),'b') for d in str(n))),2)
# Chai Wah Wu, May 10 2015

Extensions

a(0)=0 prepended and offset changed by Reinhard Zumkeller, May 10 2015