A249894 - OEIS

%I #13 Nov 17 2014 09:15:45

%S 3,36,361,361201,36120142809,3612014280924268428225,

%T 361201428092426842822525044572369542546150009

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

%H Hiroaki Yamanouchi, <a href="/A249894/b249894.txt">Table of n, a(n) for n = 1..10</a>

%o (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++)

%o a(3)

%o (Python)

%o def f(x):

%o ..print(x, end=', ')

%o ..n = x

%o ..s = 1

%o ..while s < 10**7:

%o ....if s % 10:

%o ......S = str(s**2)

%o ......if S.startswith(str(n)):

%o ........print(s**2, end=', ')

%o ........n = s**2

%o ....s += 1

%o f(3)

%Y Cf. A048559, A048561.

%K nonn,base

%O 1,1

%A _Derek Orr_, Nov 08 2014

%E a(7) corrected by _Hiroaki Yamanouchi_, Nov 17 2014