A127891 Smallest n-digit left-truncatable prime.

2, 13, 113, 1223, 12113, 121283, 1237547, 12184967, 124536947, 1219861613, 12181833347, 121339693967, 1213536676883, 12673876537547, 121848768729173, 1275463876537547, 12429121339693967, 165678739293946997, 1276812967623946997, 15396334245663786197, 315396334245663786197, 5918918997653319693967, 57686312646216567629137, 357686312646216567629137

Offset

1,1

Comments

Ends at a(24) = 357686312646216567629137.

Agrees with A088604 for 24 terms, but this sequence ends there while A088604 continues.

Links

Ray Chandler, Table of n, a(n) for n = 1..24

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

Index entries for sequences related to truncatable primes

Mathematica

grow[p_, digits_] := Select[ Table[ FromDigits[Join[{k}, IntegerDigits[p]]], {k, 1, 9}], PrimeQ[#] && Length[ IntegerDigits[#]] == digits&]; g[1] = {3, 7}; g[n_] := g[n] = grow[#, n]& /@ g[n-1] // Flatten; a[1] = 2; a[n_] := Min[g[n]]; Table[a[n], {n, 1, 24}] (* Jean-François Alcover, Aug 05 2013 *)

Crossrefs

Cf. A024785, A050987, A088604, A127892.

Sequence in context: A096497 A247153 A088604 * A110369 A212071 A258620

Adjacent sequences: A127888 A127889 A127890 * A127892 A127893 A127894

Keyword

base,nonn,fini,full

Author

Ray Chandler, Feb 04 2007

Status

approved