A249894 a(n+1) is next smallest square not divisible by 10 beginning with a(n), initial term is 3.

3, 36, 361, 361201, 36120142809, 3612014280924268428225, 361201428092426842822525044572369542546150009

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(3)

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(3)

Extensions

a(7) corrected by Hiroaki Yamanouchi, Nov 17 2014