A032650 Lucky numbers that are concatenations of a number k with itself.

33, 99, 2121, 2323, 5151, 5959, 6363, 7171, 7575, 8787, 8989, 9999, 105105, 111111, 117117, 123123, 129129, 135135, 143143, 147147, 153153, 171171, 173173, 177177, 191191, 201201, 237237, 243243, 255255, 263263, 285285, 305305, 309309, 317317

Offset

1,1

Links

Kevin P. Thompson, Table of n, a(n) for n = 1..4215 (first 95 terms from Amiram Eldar)

Formula

a(n) = A032640(n) || A032640(n), where || denotes concatenation. - Kevin P. Thompson, Nov 09 2021

Crossrefs

Intersection of A000959 and A020338.

Cf. A032640.

Sequence in context: A044601 A195315 A098441 * A284986 A133901 A008880

Adjacent sequences: A032647 A032648 A032649 * A032651 A032652 A032653

Keyword

nonn,base

Author

Patrick De Geest, May 15 1998

Extensions

More terms from Sascha Kurz, Mar 24 2002

Edited by Charles R Greathouse IV, Apr 26 2010

Status

approved