Revision History for A037271
(Underlined text is an addition;
strikethrough text is a deletion.)
Showing entries 1-10
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| A037271
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Number of steps to reach a prime under "replace n with concatenation of its prime factors" when applied to n-th composite number, or -1 if no such number exists.
(history;
published version)
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#39 by Joerg Arndt at Sat Dec 11 04:34:57 EST 2021
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#38 by Michel Marcus at Sat Dec 11 04:17:46 EST 2021
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#37 by Michel Marcus at Sat Dec 11 04:17:42 EST 2021
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| LINKS
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P. Patrick De Geest, <a href="http://www.worldofnumbers.com/topic1.htm">Home Primes</a>
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| STATUS
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proposed
editing
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#36 by Jon E. Schoenfield at Sat Dec 11 04:17:13 EST 2021
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#35 by Jon E. Schoenfield at Sat Dec 11 04:17:09 EST 2021
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| NAME
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Number of steps to reach a prime under "replace n with concatenation of its prime factors" when applied to n-th composite number, or -1 if no such number exists.
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| STATUS
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approved
editing
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#34 by Jon E. Schoenfield at Fri Mar 31 22:47:34 EDT 2017
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#33 by Jon E. Schoenfield at Fri Mar 31 22:47:31 EDT 2017
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| NAME
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Number of steps to reach a prime under "replace n bywith concatenation of its prime factors" when applied to n-th composite number, or -1 if no such number.
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approved
editing
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#32 by Giovanni Resta at Mon Mar 20 10:01:19 EDT 2017
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#31 by Giovanni Resta at Mon Mar 20 10:00:59 EDT 2017
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| DATA
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2, 1, 1913, 2, 4, 1, 5, 4, 4, 1, 15, 1, 1, 2, 3, 4, 4, 1, 2, 2, 1, 5, 3, 2, 2, 1, 9, 2, 9, 6, 1, 15
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| EXTENSIONS
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Corrected by Ray G. Opao (qzxpqbp(AT)gmail.com), Mar 20 2017
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proposed
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#30 by Ray G. Opao at Mon Mar 20 09:31:53 EDT 2017
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Discussion
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| Mon Mar 20
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| Ray G. Opao: please delete this proposed change. i finally realize my mistake. the primes were not arranged in ascending order. sorry.
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| 10:00
| Giovanni Resta: I think that your correction is wrong. I obtain 13 steps, for a(3), which corresponds to starting from 8 and obtaining the following numbers : 8, 222, 2337, 31941, 33371313, 311123771, 7149317941, 22931219729,
112084656339, 3347911118189, 11613496501723, 97130517917327,
531832651281459, 3331113965338635107 with this last one prime. The fatorizations are 8 = 2^3, 222=2*3*37, 2337=3*19*41, 31941=3^3*7*13^2, 33371313 = 7*149*317*941, 7149317941 = 229*31219729, 22931219729=11*2084656339, 112084656339=3*347*911*118189, 3347911118189=11*613*496501723, 11613496501723 = 97*130517*917327, 97130517917327 =53*1832651281459, 531832651281459=3^3*11*139*653*3863*5107 and 3331113965338635107 is prime.
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