OFFSET
1,3
COMMENTS
A subsequence of A010784. - FUNG Cheok Yin, Jul 05 2018
LINKS
FUNG Cheok Yin, Table of n, a(n) for n = 1..1082
EXAMPLE
The keypad is:
+---+---+---+
| 7 | 8 | 9 |
+---+---+---+
| 4 | 5 | 6 |
+---+---+---+
| 1 | 2 | 3 |
+---+---+---+
| 0 | x |
+---+---+---+
It is visibly obvious that 5210 can be formed on the keypad.
CROSSREFS
KEYWORD
nonn,fini,base,full
AUTHOR
FUNG Cheok Yin, Feb 02 2017
EXTENSIONS
Initial 0 added by N. J. A. Sloane, Feb 05 2017
STATUS
approved