cp's OEIS Frontend

A281943 Nonnegative numbers whose digits can be formed by typing adjacent keys on a 789-456-123-00X keypad without repeating a digit.

%I A281943 #33 Jul 08 2018 02:36:28
%S A281943 0,1,2,3,4,5,6,7,8,9,10,12,14,20,21,23,25,32,36,41,45,47,52,54,56,58,
%T A281943 63,65,69,74,78,85,87,89,96,98,102,120,123,125,145,147,201,210,214,
%U A281943 236,254,256,258,320,321,325,365,369,410,412,452,456,458,478,520,521,523,541,547,563,569,587
%N A281943 Nonnegative numbers whose digits can be formed by typing adjacent keys on a 789-456-123-00X keypad without repeating a digit.
%C A281943 A subsequence of A010784. - _FUNG Cheok Yin_, Jul 05 2018
%H A281943 FUNG Cheok Yin, <a href="/A281943/b281943.txt">Table of n, a(n) for n = 1..1082</a>
%e A281943 The keypad is:
%e A281943 +---+---+---+
%e A281943 | 7 | 8 | 9 |
%e A281943 +---+---+---+
%e A281943 | 4 | 5 | 6 |
%e A281943 +---+---+---+
%e A281943 | 1 | 2 | 3 |
%e A281943 +---+---+---+
%e A281943 |   0   | x |
%e A281943 +---+---+---+
%e A281943 It is visibly obvious that 5210 can be formed on the keypad.
%Y A281943 Cf. A010784, A280593, A280594, A280595, A281942, A215009.
%K A281943 nonn,fini,base,full
%O A281943 1,3
%A A281943 _FUNG Cheok Yin_, Feb 02 2017
%E A281943 Initial 0 added by _N. J. A. Sloane_, Feb 05 2017