A050741 Numbers k such that the decimal expansion of k^2 contains no pair of consecutive equal digits.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 14, 16, 17, 18, 19, 22, 23, 24, 25, 26, 27, 28, 29, 31, 32, 33, 36, 37, 39, 41, 42, 43, 44, 45, 48, 49, 51, 52, 53, 54, 55, 56, 57, 59, 61, 63, 64, 66, 68, 69, 71, 72, 73, 74, 75, 77, 78, 79, 81, 82, 84, 86, 87, 89, 91, 92, 93, 95, 96, 97

Offset: 1

Author

Patrick De Geest, Sep 15 1999

Keywords

• nonn
• base

Examples

			10 is absent because 10^2=100 with repeating 0,
12 is absent because 12^2=144 with repeating 4,
21 is absent because 21^2=441 with repeating 4.
		

Links

• Zak Seidov and Michael De Vlieger, Table of n, a(n) for n = 1..10471, a(n) < 25,000 (First 1057 terms from Zak Seidov)

Crossrefs

Cf. A043096, A050749, A135463, A134962.

Programs

Mathematica

Select[Range[0,97],FreeQ[Differences[IntegerDigits[#^2]],0]&] (* Jayanta Basu, May 31 2013 *)

Extensions

Edited by N. J. A. Sloane, Mar 16 2008