A246520 Largest number that can be written in binary as concatenation of (n - k) and (n + k), 0 <= k <= n.

0, 3, 10, 20, 36, 45, 72, 104, 136, 153, 170, 208, 272, 336, 400, 464, 528, 561, 594, 627, 660, 693, 800, 928, 1056, 1184, 1312, 1440, 1568, 1696, 1824, 1952, 2080, 2145, 2210, 2275, 2340, 2405, 2470, 2535, 2600, 2665, 2730, 2880, 3136, 3392, 3648, 3904

Offset: 0

Author

Reinhard Zumkeller, Sep 04 2014

Keywords

• nonn
• base

Comments

Largest term in row n of A246830.

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A246830, A007088, A246701 (first dfferences).

Programs

Haskell

a246520 = maximum . a246830_row

Mathematica

Table[Max[FromDigits[#,2]&/@Table[Join[IntegerDigits[n-k,2],IntegerDigits[ n+k,2]],{k,0,n}]],{n,0,50}] (* Harvey P. Dale, Oct 02 2018 *)

Python

def A246520(n):
    return(max(int(bin(n-k)[2:]+bin(n+k)[2:],2) for k in range(n+1)))
# Chai Wah Wu, Sep 07 2014