login
Odd squares in which parity of digits alternates.
4

%I #6 Aug 17 2018 10:48:02

%S 1,9,25,49,81,121,169,361,529,729,961,4761,6561,12321,12769,14161,

%T 16129,18769,32761,34969,56169,72361,74529,76729,78961,96721,212521,

%U 214369,290521,436921,452929,458329,474721,670761,690561,1038361

%N Odd squares in which parity of digits alternates.

%H Giovanni Resta, <a href="/A030156/b030156.txt">Table of n, a(n) for n = 1..10000</a>

%t altQ[n_] := n < 10 || Union[Total /@ Partition[ Mod[ IntegerDigits@n, 2], 2, 1]] == {1}; Select[ Range[1, 2000, 2]^2, altQ[#] &] (* _Giovanni Resta_, Aug 16 2018 *)

%Y Cf. A030151, A030152, A030155, A030157, A030158.

%K nonn,base

%O 1,2

%A _Patrick De Geest_

%E Offset changed by _Giovanni Resta_, Aug 16 2018