I found that one could get the (probable prime) solution for n=168 by removing 67, 71, 79, 83, 7, 97, 73, 89 from the least significant digits of the solution for n=120, and then concatenating 661, 673, 67, 677, 683, 691, 701, 709, 71, 719, 727, 733, 73, 739, 743, 751, 757, 761, 769, 773, 7, 787, 797, 79, 809, 811, 821, 823, 827, 829, 83, 839, 853, 857, 859, 863, 877, 881, 883, 887, 89, 907, 911, 919, 929, 937, 941, 947, 953, 967, 977, 991, 983, 97, 997, 971. Warut On Wed, Aug 4, 2010 at 2:46 AM, Hans Havermann <pxp@rogers.com> wrote:
I would appreciate being notified of any errors in this compilation of solutions up to 120 distinct concatenated primes:
http://chesswanks.com/seq/b083427.txt
The entries from n = 26 on all rely on the assumption that the n smallest primes are concatenated, unless the resulting number is divisible by 3, in which case the n-th prime is replaced with the first available larger prime resulting in a concatenated number not divisible by 3. I trust that this method will fail as we further approach n = 168, and then work again in the digit-regime change starting at n = 169.