A117640 Concatenation of first n numbers in base 4.

1, 12, 123, 12310, 1231011, 123101112, 12310111213, 1231011121320, 123101112132021, 12310111213202122, 1231011121320212223, 123101112132021222330, 12310111213202122233031

Offset: 1

Author

Jonathan Vos Post, Apr 27 2006

Keywords

• base
• easy
• nonn

Comments

Concatenation of the first n terms of A007090.

Base-4 analog of A058935.

Links

• N. J. A. Sloane, Table of n, a(n) for n = 1..35

Crossrefs

Cf. A030373, A048436.

Other bases: A058935 (2), A360502 (3), A007908 (10).

Programs

Mathematica

Table[FromDigits[Flatten[Table[IntegerDigits[n,4],{n,k}]]],{k,15}] (* Harvey P. Dale, Jan 18 2023 *)

Python

from gmpy2 import digits
def A117640(n): return int(''.join(digits(n,4) for n in range(1,n+1))) # Chai Wah Wu, Apr 19 2023

Extensions

Edited by Jason Kimberley, Nov 27 2012