A249182 Proceed counterclockwise on the outer keys of a numeric keypad (i.e., 1,2,3,6,9,8,7,4): first single digits, then concatenate two digits, then three, etc.

1, 2, 3, 6, 9, 8, 7, 4, 12, 23, 36, 69, 98, 87, 74, 41, 123, 236, 369, 698, 987, 874, 741, 412, 1236, 2369, 3698, 6987, 9874, 8741, 7412, 4123, 12369, 23698, 36987, 69874, 98741, 87412, 74123, 41236, 123698, 236987, 369874, 698741, 987412, 874123, 741236, 412369

Offset

1,2

Comments

k-digit terms start at index 8k-7; for example, at index 57, start the 8-digit terms 12369874, 23698741, 36987412, 69874123, 98741236, 87412369, 74123698, 41236987.

Links

Table of n, a(n) for n=1..48.

Prog

(PARI) d=Vec("12369874"); for(L=1, 6, for(i=1, #d, print1(concat(vector(L, j, d[(i+j-2)%#d+1]))", ")))

Crossrefs

Cf. A059805, A091331, A091332, A249163.

Sequence in context: A358850 A021426 A309008 * A189968 A097108 A140783

Adjacent sequences: A249179 A249180 A249181 * A249183 A249184 A249185

Keyword

nonn,base

Author

M. F. Hasler, Oct 23 2014

Status

approved