The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A056129 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A056129

Final nonzero digit of n-th primorial.
(history; published version)

#11 by Charles R Greathouse IV at Tue Dec 03 11:40:12 EST 2024

STATUS

editing

approved

#10 by Charles R Greathouse IV at Tue Dec 03 11:40:09 EST 2024

COMMENTS

For n > 2, a(n) is in {1, 3, 7, 9}.

FORMULA

a(n) = prime(n)#/10 mod 10 for n > 2. - Charles R Greathouse IV, Dec 03 2024

PROG

(PARI) a(n)=if(n<3, return([1, 2, 6][n+1])); my(m=Mod(3, 10)); forprime(p=7, prime(n), m*=p); lift(m) \\ Charles R Greathouse IV, Dec 03 2024

STATUS

approved

editing

#9 by Georg Fischer at Sat Feb 26 13:48:40 EST 2022

STATUS

editing

approved

#8 by Georg Fischer at Sat Feb 26 13:48:33 EST 2022

CROSSREFS

Cf. A002110, A008904.

STATUS

approved

editing

#7 by Russ Cox at Fri Mar 30 17:30:25 EDT 2012

AUTHOR

_Robert G. Wilson v (rgwv(AT)rgwv.com), _, Jul 28 2000

Discussion

Fri Mar 30

17:30

OEIS Server: https://oeis.org/edit/global/156

#6 by Russ Cox at Sun Jul 10 18:42:56 EDT 2011

LINKS

<a href="/Sindx_index/Fi.html#final">Index entries for sequences related to final digits of numbers</a>

Discussion

Sun Jul 10

18:42

OEIS Server: https://oeis.org/edit/global/40

#5 by N. J. A. Sloane at Thu Nov 11 07:34:06 EST 2010

LINKS

<a href="/Sindx_Fi.html#final">Index entries for sequences related to final digits of numbers</a>

KEYWORD

easy,nonn,base,new

#4 by N. J. A. Sloane at Fri Feb 27 03:00:00 EST 2009

LINKS

<a href="http://www.research.att.com/~njas/sequences/Sindx_Fi.html#final">Index entries for sequences related to final digits of numbers</a>

KEYWORD

easy,nonn,base,new

#3 by N. J. A. Sloane at Fri Jan 09 03:00:00 EST 2009

KEYWORD

easy,nonn,newbase

#2 by N. J. A. Sloane at Sat Jun 12 03:00:00 EDT 2004

NAME

Final non-zero nonzero digit of n-th primorial.

KEYWORD

easy,nonn,new