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A281943 Nonnegative numbers whose digits can be formed by typing adjacent keys on a 789-456-123-00X keypad without repeating a digit. 2
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, 63, 65, 69, 74, 78, 85, 87, 89, 96, 98, 102, 120, 123, 125, 145, 147, 201, 210, 214, 236, 254, 256, 258, 320, 321, 325, 365, 369, 410, 412, 452, 456, 458, 478, 520, 521, 523, 541, 547, 563, 569, 587 (list; graph; refs; listen; history; text; internal format)
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

Cf. A010784, A280593, A280594, A280595, A281942, A215009.

Sequence in context: A175740 A320321 A215009 * A120003 A333223 A334967

Adjacent sequences:  A281940 A281941 A281942 * A281944 A281945 A281946

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

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Last modified April 19 03:45 EDT 2021. Contains 343105 sequences. (Running on oeis4.)