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A103443 Largest left-truncatable prime in base n (decimal expansion).

%I A103443 #60 Feb 16 2025 08:32:56
%S A103443 23,4091,7817,4836525320399,817337,14005650767869,1676456897,
%T A103443 357686312646216567629137,2276005673,
%U A103443 13092430647736190817303130065827539,812751503,615419590422100474355767356763
%N A103443 Largest left-truncatable prime in base n (decimal expansion).
%H A103443 Martin Fuller, <a href="/A103443/b103443.txt">Table of n, a(n) for n = 3..29</a>
%H A103443 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. (See also Sloane link below)
%H A103443 James Grime and Brady Haran, <a href="https://www.youtube.com/watch?v=azL5ehbw_24">357686312646216567629137</a>, Numberphile video (2018).
%H A103443 Martin Renner, <a href="/A103443/a103443.txt">Table of n, a(n) for n = 3..53 (with some question marks)</a>. Corrected and expanded by Hans Havermann, Jan 25 2014.
%H A103443 N. J. A. Sloane, <a href="/A023107/a023107.txt">The Angell-Godwin table of initial terms of A023107 and A103443</a>
%H A103443 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TruncatablePrime.html">Truncatable Prime</a>.
%H A103443 <a href="/index/Tri#tprime">Index entries for sequences related to truncatable primes</a>
%o A103443 (PARI) a(n)=my(v=primes(primepi(n-1)),u,t,b=1,best); while(#v, best=vecmax(v); b*=n; u=List(); for(i=1,#v,for(k=1,n-1,if(isprime(t=v[i]+k*b), listput(u,t)))); v=Vec(u)); best \\ _Charles R Greathouse IV_, Feb 05 2013
%Y A103443 Cf. A076623, A023107, A103463, A254755.
%K A103443 nonn,base
%O A103443 3,1
%A A103443 _Martin Renner_, Mar 21 2005, Sep 24 2007, Apr 20 2008
%E A103443 Base-14 entry corrected by _Hans Havermann_, May 30 2011
%E A103443 Corresponding entry in a-file corrected by _N. J. A. Sloane_, Jun 02 2011
%E A103443 a-file corrected and expanded by _Hans Havermann_, Jan 25 2014