A359124 Concatenate the decimal numbers 1,2,3,...,n, then add 1.

2, 13, 124, 1235, 12346, 123457, 1234568, 12345679, 123456790, 12345678911, 1234567891012, 123456789101113, 12345678910111214, 1234567891011121315, 123456789101112131416, 12345678910111213141517, 1234567891011121314151618, 123456789101112131415161719, 12345678910111213141516171820

Offset: 1

Author

N. J. A. Sloane, Dec 20 2022

Keywords

• nonn
• base

Comments

a(n) = A007908(n)+1.

Studied in A069048.

Crossrefs

Cf. A007908, A069048, A359125.

Programs

Mathematica

Table[FromDigits[Flatten[IntegerDigits/@Range[n]]]+1,{n,20}] (* Harvey P. Dale, Dec 20 2022 *)

Python

def a(n): return int("".join(map(str, range(1, n+1)))) + 1
print([a(n) for n in range(1, 20)]) # Michael S. Branicky, Dec 20 2022