A030156 Odd squares in which parity of digits alternates.

1, 9, 25, 49, 81, 121, 169, 361, 529, 729, 961, 4761, 6561, 12321, 12769, 14161, 16129, 18769, 32761, 34969, 56169, 72361, 74529, 76729, 78961, 96721, 212521, 214369, 290521, 436921, 452929, 458329, 474721, 670761, 690561, 1038361

Offset

1,2

Links

Giovanni Resta, Table of n, a(n) for n = 1..10000

Mathematica

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 *)

Crossrefs

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

Sequence in context: A016754 A110487 A259417 * A331587 A192775 A318737

Adjacent sequences: A030153 A030154 A030155 * A030157 A030158 A030159

Keyword

nonn,base

Author

Patrick De Geest

Extensions

Offset changed by Giovanni Resta, Aug 16 2018

Status

approved