A032650 - OEIS

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A032650

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

3

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

(list; graph; refs; listen; history; text; internal format)

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.

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