The numbers are just the sum of digits of the primes.
1+1=2
1+3=4
1+7=8
1+9=10
2+3=5
2+9=11

My first solution is equivalent but more complicated:  each prime minus 9 times its tens digit.  Although I made the error of considering 27 prime instead of 29.

Posted by Jer on 2014-09-25 09:50:59