_Parthasarathy Nambi (PachaNambi(AT)yahoo.com), _, Jul 09 2009

proposed

approved

If there is more than one occurrence of the smallest or the largest digit, only one is counted.

947 is a prime in which the sum of the smallest digit (4) and the largest digit (9) is a an odd prime (13).

Primes such that the sum of its smallest digit and the largest digit decimal digits is also a an odd prime.

The smallest and the largest digit must be distinct - that is primes like 11 are ignored. Single digit primes are ignored. If there is more than one occurrence of the smallest or the largest digit, only one is counted.

Chris Caldwell, <a href="http://primes.utm.edu/lists/small/1000.txt">The First 1,000 Primes</a>

nonn,newbase

approved

proposed

Primes such that the sum of its smallest digit and the largest digit is also a prime.

23, 29, 41, 47, 61, 67, 83, 103, 107, 163, 211, 223, 229, 233, 241, 269, 293, 307, 383, 421, 431, 433, 443, 449, 457, 461, 467, 479, 491, 499, 503, 509, 523, 547, 587, 607, 613, 631, 641, 661, 677, 701, 829, 853, 857, 863, 883, 929, 947

1,1

The smallest and the largest digit must be distinct - that is primes like 11 are ignored. Single digit primes are ignored. If there is more than one occurrence of the smallest or the largest digit, only one is counted.

Chris Caldwell, <a href="http://primes.utm.edu/lists/small/1000.txt">The First 1,000 Primes</a>

947 is a prime in which the sum of the smallest digit (4) and the largest digit (9) is a prime.

A046704, A070027, A086244, A088136, A091939, A109981

nonn

Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Jul 09 2009

approved