cp's OEIS Frontend

A343726 Squares with exactly one even digit.

%I A343726 #19 May 23 2021 00:19:22
%S A343726 0,4,16,25,36,49,81,121,169,196,361,529,576,729,961,1156,1369,1521,
%T A343726 1936,3136,3721,3969,5329,5776,5929,7396,7569,7921,15129,15376,17161,
%U A343726 17956,19321,31329,35721,51529,53361,57121,59536,97969,111556,113569,119716,131769
%N A343726 Squares with exactly one even digit.
%C A343726 The even digit is always one of the last two digits.
%C A343726 The only squares with no digits even are the one-digit odd squares 1 and 9.
%H A343726 Jianing Song, <a href="/A343726/b343726.txt">Table of n, a(n) for n = 1..10000</a>
%F A343726 Intersection of A000290 and A118070.
%p A343726 q:= n-> (l-> is(add(i mod 2, i=l)=nops(l)-1))(convert(n, base, 10)):
%p A343726 select(q, [i^2$i=0..400])[];  # _Alois P. Heinz_, May 22 2021
%t A343726 Select[Range[0, 400]^2, Count[IntegerDigits[#], _?EvenQ] == 1 &] (* _Amiram Eldar_, May 21 2021 *)
%o A343726 (Python)
%o A343726 def ok(sq): return sum(d in "02468" for d in str(sq)) == 1
%o A343726 def aupto(limit):
%o A343726   sqs = (i*i for i in range(int(limit**.5)+2) if i*i <= limit)
%o A343726   return list(filter(ok, sqs))
%o A343726 print(aupto(131769)) # _Michael S. Branicky_, May 20 2021
%o A343726 (PARI) isA343726(n) = if(issquare(n) && (n!=0), my(d=digits(n)); #d - vecsum(d%2) == 1, n==0) \\ _Jianing Song_, May 22 2021
%Y A343726 Cf. A000290, A030098, A118070, A343724, A343725.
%K A343726 nonn,base
%O A343726 1,2
%A A343726 _Jon E. Schoenfield_, May 19 2021