A242589 Primes p such that p = the cumulative sum of the digit-sum in base 15 of the digit-product in base 4 of each prime < p.

5, 19, 37, 43, 97, 107, 6091, 6389, 7121, 21727, 147107, 148151, 148279, 148429, 148469, 172877, 173209, 173741, 2621387, 5642293, 5642321, 8932771, 8981827, 8981879, 9094979, 9095089, 9997783, 10010687, 10010789, 10037749, 10144523, 40179929, 40365217, 40379077, 40379197, 40386811, 40612933

Offset: 1

Author

Anthony Sand, May 20 2014

Keywords

• nonn
• base

Examples

			5 = digit-sum(digit-mult(2,b=4),b=15) + sum(mult(3,b=4),b=15) = 2 + 3.
19 = digit-sum(digit-mult(2,b=4),b=15) + sum(mult(3,b=4),b=15) + sum(mult(11,b=4),b=15) + sum(mult(13,b=4),b=15) + sum(mult(23,b=4),b=15) + sum(mult(31,b=4),b=15) + sum(mult(101,b=4),b=15) = 2 + 3 + 1 + 3 + 6 + 3 + 1.
		

Crossrefs

Cf. A240886 (similar sequence with digit sums in base 3).

Formula

sum = sum + digit-sum(digit-mult(prime,base=4),base=15). The function digit-mult(n) multiplies all digits d of n, where d > 0. For example, digit-mult(1230) = 1 * 2 * 3 = 6. Therefore, the digit-sum in base 15 of the digit-mult(333) in base 4 = digit-sum(3 * 3 * 3) = digit-sum(1C) = 1 + C = 13. (1C in base 15 = 27 in base 10).