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A229129 Digital clock palindromic semiprimes. 0
4, 6, 9, 22, 33, 55, 111, 121, 141, 202, 303, 323, 505, 515, 535, 545, 626, 707, 717, 737, 939, 949, 959, 1111, 1441 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Palindromic semiprimes possible on a 24-hour digital clock, with no seconds. This is similar to A229107 as semiprimes (A001358) are to prime A000040, except this sequence has no seconds.

LINKS

Table of n, a(n) for n=1..25.

FORMULA

Digital clock semiprimes (A129336) INTERSECTION Palindromes in base 10 (A002113).

CROSSREFS

Cf. A001358, A002113, A229107.

Sequence in context: A046328 A196104 A046376 * A272436 A246569 A085721

Adjacent sequences:  A229126 A229127 A229128 * A229130 A229131 A229132

KEYWORD

nonn,base,fini,full

AUTHOR

Jonathan Vos Post, Sep 14 2013

STATUS

approved

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Last modified December 13 22:42 EST 2018. Contains 318087 sequences. (Running on oeis4.)