login
A050741
Numbers k such that the decimal expansion of k^2 contains no pair of consecutive equal digits.
4
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
1,3
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)
EXAMPLE
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.
MATHEMATICA
Select[Range[0, 97], FreeQ[Differences[IntegerDigits[#^2]], 0]&] (* Jayanta Basu, May 31 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Sep 15 1999
EXTENSIONS
Edited by N. J. A. Sloane, Mar 16 2008
STATUS
approved