A032650 - OEIS

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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

(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.

Cf. A032640.

Sequence in context: A044601 A195315 A098441 * A284986 A133901 A008880

Adjacent sequences: A032647 A032648 A032649 * A032651 A032652 A032653