A045860 Numbers whose square has initial digit '6'.

8, 25, 26, 78, 79, 80, 81, 82, 83, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 775, 776, 777, 778, 779, 780, 781, 782, 783, 784, 785, 786, 787, 788, 789, 790, 791, 792, 793, 794, 795, 796, 797, 798, 799

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

Flatten[Table[Range[Ceiling[Sqrt[6*10^n]], Floor[Sqrt[7*10^n]]], {n, 5}]] (* Harvey P. Dale, Apr 03 2013 *)

Prog

(Python)
from math import isqrt
def aupto(limit):
    alst, d, end = [], 1, 0
    while end < limit:
        start, end = isqrt(6*10**d) + 1, isqrt(7*10**d-1)
        alst.extend([an for an in list(range(start, end+1)) if an <= limit])
        d += 1
    return alst
print(aupto(799)) # Michael S. Branicky, Aug 25 2021

Crossrefs

Supersequence of A035073.

Cf. A045789.

Sequence in context: A254341 A188477 A302632 * A081504 A030796 A266927

Adjacent sequences: A045857 A045858 A045859 * A045861 A045862 A045863

Keyword

nonn,base

Author

Jeff Burch

Status

approved