1,1

Maple worksheet available upon request. Here is the minimal set in base 12 where X is 10 and E is 11. 2, 3, 5, 7, E, 11, 61, 81, 91, 401, X41, 4441, X0X1, XXXX1, 44XXX1, XXX0001, XX000001. This minimal set demonstrates the elegance of base 12 generally since you can mentally follow the process of elimination, all primes after E end in the neutral digit 1, and the last two entries only contain X, 0, and 1. There are no primes of the form X0...01 since the sum of its digits is E and hence it is divisible by E.

a(10)=401 since no earlier prime in the list contained the pattern "*4*0*1*" where "*" stands for zero or more digits. The list can be manually constructed using a sieve-like process: eliminate all subsequent primes of the form "*4*0*1*" from the list of all primes. Assuming all previous elements have also been similarly determined, the next remaining prime should be X41.

Cf. A071062, A071070.

Adjacent sequences: A110597 A110598 A110599 this_sequence A110601 A110602 A110603

Sequence in context: A128292 A037174 A037949 this_sequence A029979 A029981 A029982

nonn

Walter A. Kehowski (wkehowski(AT)cox.net), Sep 14 2005