A215533 Numbers n such that n^s(n) + 1 is a prime, where s(n) is the sum of the digits of n.

1, 2, 4, 10, 20, 100, 110, 152, 220, 242, 736, 790, 800, 916, 1010, 1078, 1106, 1232, 1528, 1636, 1834, 2284, 2330, 2392, 2600, 3100, 3562, 3904, 4000, 4066, 4228, 4444, 4552, 5056, 6082, 6208, 6226, 7810, 8170, 8530, 9520

Offset: 1

Author

Vicente Izquierdo Gomez, Aug 15 2012

Keywords

• nonn
• base

Programs

Mathematica

t = {}; Do[If[PrimeQ[(n^Total[IntegerDigits[n]]) + 1], AppendTo[t, n]], {n, 10000}]; t
Select[Range[10000],PrimeQ[#^Total[IntegerDigits[#]]+1]&] (* Harvey P. Dale, Aug 26 2019 *)