Clock Prime
المؤلف:
Sloane, N. J. A.
المصدر:
Sequences A036342, A036343, A036344, and A050246 in "The On-Line Encyclopedia of Integer Sequences."
الجزء والصفحة:
...
13-1-2021
1451
Clock Prime
A prime number obtained by reading digits around an analog clock. In a clockwise direction, the primes are 2, 3, 5, 7, 11, 23, 67, 89, 4567, 23456789, 23456789101112123, ... (OEIS A036342). In a counterclockwise direction, the primes are 2, 3, 5, 7, 11, 43, 109, 10987, 76543, 6543211211, 4321121110987, ... (OEIS A036342). In either direction, the primes are 2, 3, 5, 7, 11, 23, 43, 67, 89, 109, 4567, 10987, 76543, 23456789, 6543211211, ... (OEIS A036344).
On a 24-hour digital clock, there are 211 possible prime values: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 101, ... (OEIS A050246).
REFERENCES:
Rivera, C. "Problems & Puzzles: Puzzle 019-Primes on a Clock." https://www.primepuzzles.net/puzzles/puzz_019.htm.
Sloane, N. J. A. Sequences A036342, A036343, A036344, and A050246 in "The On-Line Encyclopedia of Integer Sequences."
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