A249895 a(n+1) is next smallest square not divisible by 10 beginning with a(n), initial term is 5.

5, 529, 529984, 52998485796, 5299848579629072273476, 529984857962907227347600150092608188876380736

Offset: 1

Author

Derek Orr, Nov 08 2014

Keywords

• nonn
• base

Links

• Hiroaki Yamanouchi, Table of n, a(n) for n = 1..10

Crossrefs

Cf. A048559, A048561.

Programs

PARI

a(n)=k=n; s=1; while(s<5*10^7, if(s%10, if(s^2\(10^(#Str(s^2)-#Str(k)))==k, print1(s^2, ", "); k=s^2)); s++)
a(5)

Python

def f(x):
  print(x, end=', ')
  n = x
  s = 1
  while s < 10**7:
    if s % 10:
      S = str(s**2)
      if S.startswith(str(n)):
        print(s**2, end=', ')
        n = s**2
    s += 1
f(5)