The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A047814 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A047814

Largest prime substring of n, or 0 if no such substring exists.
(history; published version)

#22 by Wesley Ivan Hurt at Fri Dec 29 23:18:34 EST 2023

STATUS

editing

approved

#21 by Wesley Ivan Hurt at Fri Dec 29 23:18:17 EST 2023

CROSSREFS

Cf. A211396.

STATUS

approved

editing

#20 by Jon E. Schoenfield at Sat Jun 24 13:42:23 EDT 2017

STATUS

editing

approved

#19 by Jon E. Schoenfield at Sat Jun 24 13:42:20 EDT 2017

AUTHOR

N. J. A. Sloane.

STATUS

approved

editing

#18 by Harvey P. Dale at Wed Feb 26 17:23:08 EST 2014

STATUS

editing

approved

#17 by Harvey P. Dale at Wed Feb 26 17:23:03 EST 2014

MATHEMATICA

lps[m_]:=Max[Select[Flatten[Table[FromDigits/@Partition[ IntegerDigits[ m], n, 1], {n, IntegerLength[m]}]], PrimeQ]]; Array[lps, 100, 0]/. -\[Infinity]->0 (* Harvey P. Dale, Feb 26 2014 *)

STATUS

approved

editing

#16 by Reinhard Zumkeller at Mon Jan 27 08:06:35 EST 2014

STATUS

editing

approved

#15 by Reinhard Zumkeller at Mon Jan 27 08:01:02 EST 2014

KEYWORD

nonn,easy,base,nice,look

STATUS

approved

editing

#14 by Charles R Greathouse IV at Thu Nov 21 13:11:21 EST 2013

MATHEMATICA

a[n_] := (id = IntegerDigits[n]; lg = Length[id]; sel = Select[ FromDigits /@ Flatten[ Table[ id[[i ;; j]], {i, 1, lg}, {j, i, lg}], 1], PrimeQ]; If[ sel === {}, 0, Last[ Sort[ sel] ] ]); Table[ a[n], {n, 0, 99}] (* From _Jean-François Alcover, _, Feb 23 2012 *)

Discussion

Thu Nov 21

13:11

OEIS Server: https://oeis.org/edit/global/2066

#13 by Charles R Greathouse IV at Sat Jul 13 12:02:09 EDT 2013

LINKS

_Reinhard Zumkeller_, , <a href="/A047814/b047814.txt">Table of n, a(n) for n = 0..10000</a>

Discussion

Sat Jul 13

12:02

OEIS Server: https://oeis.org/edit/global/1934