The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A023107 Largest integer in which every prefix is prime in base n (written in base 10). 17
 71, 191, 2437, 108863, 6841, 4497359, 1355840309, 73939133, 6774006887, 18704078369, 122311273757, 6525460043032393259, 927920056668659, 16778492037124607, 4928397730238375565449, 5228233855704101657, 3013357583408354653, 1437849529085279949589, 101721177350595997080671, 185720479816277907890970001 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,1 COMMENTS Or, largest right-truncatable prime with base n>2 (in decimal form). a(n) <= A094335(n). LINKS Martin Renner, Max Alekseyev and Giovanni Resta, Table of n, a(n) for n = 3..100 I. O. Angell and H. J. Godwin, On Truncatable Primes, Math. Comput. 31, 265-267, 1977. N. J. A. Sloane, The Angell-Godwin table of initial terms of A023107 and A103443 Eric Weisstein's World of Mathematics, Truncatable Prime. Index entries for sequences related to truncatable primes EXAMPLE a(100) = 70123916363515199416199518301698321195339012727994799// 190371992151279729974757397909992327936943877127375781091143. - Giovanni Resta, Apr 11 2016 PROG (PARI) a(n) = my(S, m, D); D=select(x->(gcd(x, n)==1), vector(n-1, j, j)); S=select(ispseudoprime, vector(n-1, i, i)); while(#S, m=vecmax(S); S=concat(vector(#D, j, select(ispseudoprime, vector(#S, i, S[i]*n+D[j])))); ); m /* Max Alekseyev, Dec 09 2014 */ CROSSREFS Cf. A076586. Sequence in context: A295835 A139991 A140007 * A174370 A174454 A142808 Adjacent sequences: A023104 A023105 A023106 * A023108 A023109 A023110 KEYWORD nonn,base AUTHOR David W. Wilson EXTENSIONS More terms from Don Reble, Jun 23 2004 a(54)-a(75) in b-file from Max Alekseyev, Dec 09 2014 a(76)-a(100) in b-file from Giovanni Resta, May 01 2016 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 15 13:23 EDT 2024. Contains 375938 sequences. (Running on oeis4.)