A035075 a(n) = ceiling(sqrt(8*10^n)).

9, 29, 90, 283, 895, 2829, 8945, 28285, 89443, 282843, 894428, 2828428, 8944272, 28284272, 89442720, 282842713, 894427191, 2828427125, 8944271910, 28284271248, 89442719100, 282842712475, 894427191000, 2828427124747

Offset: 1

Author

Patrick De Geest, Nov 15 1998

Keywords

• nonn
• base

Comments

Also, first term of runs of consecutive numbers whose square starts with the digit 8.

Crossrefs

Cf. A067478 (squares), A035069-A035076 (2..9), A045862.

Programs

Mathematica

Ceiling[Sqrt[8*10^Range[30]]] (* Harvey P. Dale, Apr 12 2013 *)

Python

from math import isqrt
def a(n): return isqrt(8*10**n) + 1
print([a(n) for n in range(1, 25)]) # Michael S. Branicky, Sep 29 2021

Formula

a(n) = ceiling(sqrt(8*10^n)), n > 0.