On average, there are as many prime numbers for which the sum of decimal digits is even as prime numbers for which it is odd. This hypothesis, first made in 1968, has recently been proven by ...

CHRISTOPHER N. SWANSON, MAXIMIZING THE SUM OF THREE-DIGIT NUMBERS CONSISTING OF THE DIGITS 1 THROUGH 9, Pi Mu Epsilon Journal, Vol. 13, No. 7 (Fall 2012), pp. 421-426 ...