The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A130139 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A130139

Let f denote the map that replaces k with the concatenation of its nontrivial divisors, written in increasing order, each divisor being written in base 10 in the normal way. Then a(n) = prime reached when starting at 2n+1 and iterating f.
(history; published version)

#24 by Michael De Vlieger at Thu Mar 09 08:40:45 EST 2023

STATUS

reviewed

approved

#23 by Joerg Arndt at Thu Mar 09 06:25:26 EST 2023

STATUS

proposed

reviewed

#22 by Michel Marcus at Thu Mar 09 06:01:17 EST 2023

STATUS

editing

proposed

#21 by Michel Marcus at Thu Mar 09 05:51:38 EST 2023

NAME

Let f denote the map that replaces k with the concatenation of its proper nontrivial divisors, written in increasing order, each divisor being written in base 10 in the normal way. Then a(n) = prime reached when starting at 2n+1 and iterating f.

EXTENSIONS

Name edited by Michel Marcus, Mar 09 2023

STATUS

approved

editing

#20 by Michael De Vlieger at Tue Mar 07 07:41:20 EST 2023

STATUS

reviewed

approved

#19 by Joerg Arndt at Tue Mar 07 02:43:36 EST 2023

STATUS

proposed

reviewed

#18 by Michel Marcus at Tue Mar 07 02:31:08 EST 2023

STATUS

editing

proposed

#17 by Michel Marcus at Tue Mar 07 02:30:45 EST 2023

KEYWORD

nonn,base,more,nonn,changed

Discussion

Tue Mar 07

02:31

Michel Marcus: if it were none it would be in the data

#16 by Michel Marcus at Tue Mar 07 02:30:21 EST 2023

EXTENSIONS

The value of a(22) is currently unknown.

STATUS

proposed

editing

#15 by Tyler Busby at Tue Mar 07 02:23:20 EST 2023

STATUS

editing

proposed