A241072 Valid groups of final digits a square number made entirely of the digits 6, 7 and 8 can have.

6, 76, 676, 776, 876, 6676, 7776, 7876, 8676, 67776, 67876, 68676, 76676, 77776, 87776, 87876, 88676, 667776, 667876, 668676, 676676, 677776, 687876, 688676, 767876, 768676, 776676, 787776, 787876, 788676, 867776, 867876, 868676, 876676, 877776, 887876, 888676

Offset

1,1

Links

Table of n, a(n) for n=1..37.

Patrick De Geest, Squares made of 3 distinct digits

Example

66 is not in this sequence because a square number cannot end in 66; a square ending in 6 must have 1, 3, 5, 7, or 9 as its next-to-last digit.

Mathematica

eLim = 6; nn = 10^eLim; t = {}; s1 = Select[Range[nn]^2, Mod[#, 10] == 6 &]; Do[s2 = Select[s1, Complement[Union[IntegerDigits[Mod[#, 10^e]]], {6, 7, 8}] == {} &]; u = Union[Mod[s2, 10^e]]; t = Union[t, u], {e, 2, eLim}]; t (* T. D. Noe, Apr 15 2014 *)

Crossrefs

Sequence in context: A229571 A016090 A181343 * A137132 A053337 A199026

Adjacent sequences: A241069 A241070 A241071 * A241073 A241074 A241075

Keyword

nonn,base

Author

J. Lowell, Apr 15 2014

Extensions

Extended by T. D. Noe, Apr 15 2014

Status

approved