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Revision History for A050986

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Showing entries 1-10 | older changes

A050986

Number of n-digit right-truncatable primes.
(history; published version)

#27 by Charles R Greathouse IV at Sun Feb 16 08:32:41 EST 2025

LINKS

Eric Weisstein's World of Mathematics, <a href="httphttps://mathworld.wolfram.com/TruncatablePrime.html">Truncatable Prime.</a>

Discussion

Sun Feb 16

08:32

OEIS Server: https://oeis.org/edit/global/3014

#26 by Bruno Berselli at Fri Jan 25 04:23:31 EST 2019

STATUS

proposed

approved

#25 by Michel Marcus at Fri Jan 25 04:05:08 EST 2019

STATUS

editing

proposed

#24 by Michel Marcus at Fri Jan 25 04:05:03 EST 2019

REFERENCES

Angell, I. O. and Godwin, H. J. "On Truncatable Primes." Math. Comput. 31, 265-267, 1977.

LINKS

I. O. Angell and H. J. Godwin, <a href="http://dx.doi.org/10.1090/S0025-5718-1977-0427213-2">On Truncatable Primes</a>, Math. Comput. 31, 265-267, 1977.

STATUS

approved

editing

#23 by N. J. A. Sloane at Fri Nov 09 21:15:26 EST 2018

STATUS

reviewed

approved

#22 by Michel Marcus at Fri Nov 09 03:21:05 EST 2018

STATUS

proposed

reviewed

Discussion

Fri Nov 09

03:27

M. F. Hasler: Wow, that was fast! ^^  - 
Should I put this pink comment (slightly better worded) as a "real" COMMENT?

21:15

N. J. A. Sloane: MFH, you said "Wow, that was fast! ^^ - Should I put this pink comment (slightly better worded) as a "real" COMMENT?" Me, sure go ahead, but I will approve this to get it off the queue

#21 by M. F. Hasler at Fri Nov 09 03:19:59 EST 2018

STATUS

editing

proposed

Discussion

Fri Nov 09

03:25

M. F. Hasler: I agree that  the sequence should be considered as full (a(n) is known and can be written here for all n) and finite (considering the nonzero terms), but it is also undisputable that a(n) is perfectly well defined for all n > 0, with a(n) = 0 for all n >= 9.

#20 by M. F. Hasler at Wed Nov 07 20:02:24 EST 2018

DATA

4, 9, 14, 16, 15, 12, 8, 5, 0

COMMENTS

Right-truncatable means that the integer part of successive divisions by 10 always yields primes (or zero). - M. F. Hasler, Nov 07 2018

PROG

(PARI) A050986=vector(9, n, #p=concat(apply(t->primes([t, t+1]*10), if(n>1, p)))) \\ M. F. Hasler, Nov 07 2018

EXTENSIONS

a(9) = 0 added by M. F. Hasler, Nov 07 2018

STATUS

approved

editing

#19 by Bruno Berselli at Fri Jun 13 18:04:16 EDT 2014

STATUS

proposed

approved

#18 by Jens Kruse Andersen at Fri Jun 13 17:05:17 EDT 2014

STATUS

editing

proposed