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A249897 a(n+1) is next smallest square not divisible by 10 beginning with a(n), initial term is 7.

%I A249897 #19 May 22 2025 10:21:41
%S A249897 7,729,729316,7293164743396,72931647433968832639882896,
%T A249897 72931647433968832639882896319584064899663299793041401
%N A249897 a(n+1) is next smallest square not divisible by 10 beginning with a(n), initial term is 7.
%H A249897 Hiroaki Yamanouchi, <a href="/A249897/b249897.txt">Table of n, a(n) for n = 1..10</a>
%o A249897 (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 A249897 a(7)
%o A249897 (Python)
%o A249897 def f(x):
%o A249897   print(x, end=', ')
%o A249897   n = x
%o A249897   s = 1
%o A249897   while s < 10**7:
%o A249897     if s % 10:
%o A249897       S = str(s**2)
%o A249897       if S.startswith(str(n)):
%o A249897         print(s**2, end=', ')
%o A249897         n = s**2
%o A249897     s += 1
%o A249897 f(7)
%Y A249897 Cf. A048559, A048561.
%K A249897 nonn,base
%O A249897 1,1
%A A249897 _Derek Orr_, Nov 08 2014
%E A249897 a(5)-a(6) corrected by _Hiroaki Yamanouchi_, Nov 17 2014