A130868 Numbers k such that the set of digits of k^2 is the same as the set of digits of (k+1)^2.

13, 157, 436, 515, 847, 863, 900, 913, 987, 992, 1010, 1100, 1213, 1350, 1358, 1686, 1784, 2015, 2183, 2263, 2313, 2342, 2597, 2778, 3186, 3279, 3347, 3486, 3536, 3592, 3649, 3779, 3899, 3909, 3913, 3971, 3986, 4012, 4099, 4248, 4284, 4286, 4291, 4412

Offset: 1

Author

Tanya Khovanova, Jul 23 2007

Keywords

• base
• nonn

Examples

			436^2 = 190096 and 437^2 = 190969 consist of the same digits (although not with the same multiplicities).
		

Crossrefs

The sequence A072841 (digits of k^2 are exactly the same (albeit in different order) as the digits of (k+1)^2) is a subsequence of this sequence.

Programs

Mathematica

Select[Range[10000], Union[IntegerDigits[ #^2]] == Union[IntegerDigits[(# + 1)^2]] &]

PARI

isok(n) = Set(digits(n^2)) == Set(digits((n+1)^2)); \\ Michel Marcus, Oct 06 2018