A201019 Primes whose multiplicative digital root is 6.

23, 47, 61, 227, 281, 283, 347, 443, 449, 467, 487, 647, 683, 743, 769, 773, 797, 821, 823, 829, 863, 887, 967, 977, 1123, 1213, 1231, 1283, 1289, 1321, 1471, 1481, 1487, 1489, 1627, 1697, 1741, 1783, 1823, 1847, 1861, 1873, 2113, 2131, 2237, 2243, 2267, 2273, 2281, 2287, 2311

Offset: 1

Author

Jaroslav Krizek, Nov 25 2011

Keywords

• nonn
• base

Comments

Complement of A201020 with respect to A034053.

Examples

			Prime 227 is in sequence because 2*2*7=28, 2*8=16, 1*6=6.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A201020 (composite numbers whose multiplicative digital root is 6), A034053 (numbers whose multiplicative digital root is 6).

Programs

Mathematica

dr6Q[n_]:=NestWhile[Times@@IntegerDigits[#]&,n,#>9&]==6; Select[ Prime[ Range[ 400]],dr6Q] (* Harvey P. Dale, Jun 16 2016 *)