The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A066457

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A066457

Numbers n such that product of factorials of digits of n equals pi(n) (A000720).
(history; published version)

#27 by Joerg Arndt at Fri Aug 14 06:43:48 EDT 2020

STATUS

reviewed

approved

#26 by Hugo Pfoertner at Fri Aug 14 06:27:49 EDT 2020

STATUS

proposed

reviewed

#25 by Michel Marcus at Fri Aug 14 03:12:47 EDT 2020

STATUS

editing

proposed

Discussion

Fri Aug 14

06:27

Hugo Pfoertner: Keep the comment for a documentation of history. It shows that significant progress has been made afterwards

#24 by Michel Marcus at Fri Aug 14 03:12:07 EDT 2020

COMMENTS

There are no other members of the sequence up to and including n=1000000. - Harvey P. Dale, Jan 07 2002

EXTENSIONS

There are no other members of the sequence up to and including n=1000000. - Harvey P. Dale, Jan 07 2002

Discussion

Fri Aug 14

03:12

Michel Marcus: I have moved Harvey extension to comment, but I am not sure it is still needed

#23 by Michel Marcus at Fri Aug 14 03:10:54 EDT 2020

EXAMPLE

pi(209210612202) = 8360755200 = 2!*0!*9!*2!*1!*0!*6!*1!*2!*2!*0!*2! . [From Qu,Shun Liang (medie2006(AT)126.com), Nov 23 2008]

EXTENSIONS

226130351 a(7) from Farideh Firoozbakht, Apr 20 2005

Four more terms a(8)-a(11) from Qu,Shun Liang (medie2006(AT)126.com), Nov 23 2008

STATUS

proposed

editing

#22 by Elijah Beregovsky at Fri Aug 14 02:49:27 EDT 2020

STATUS

editing

proposed

#21 by Elijah Beregovsky at Fri Aug 14 02:46:02 EDT 2020

LINKS

C. Caldwell and G. L. Honaker, Jr., <a href="httphttps://www.utm.edu/~staff/caldwell/paperspreprints/6521.htmlpdf">Is pi(6521)=6!+5!+2!+1! unique? </a>

STATUS

approved

editing

Discussion

Fri Aug 14

02:49

Elijah Beregovsky: Wrong link

#20 by Alois P. Heinz at Fri May 04 09:49:12 EDT 2018

STATUS

proposed

approved

#19 by Michel Marcus at Fri May 04 00:55:03 EDT 2018

STATUS

editing

proposed

#18 by Michel Marcus at Fri May 04 00:54:59 EDT 2018

PROG

(PARI) isok(n) = my(d = digits(n)); prod(k=1, #d, d[k]!) == primepi(n); \\ Michel Marcus, May 04 2018

STATUS

proposed

editing