Numbers k such that Sum_{i=1..k} i' == 0 (mod k), where i' is the arithmetic derivative of i.
A229501
Numbers k such that Sum_{i=1..k} i' == 0 (mod k), where i' is the arithmetic derivative of i.
Terms
- a(0) =1a(1) =6a(2) =344a(3) =1475a(4) =3816a(5) =5463a(6) =18468a(7) =78894a(8) =515108a(9) =566932a(10) =1600370a(11) =14380856a(12) =27129564a(13) =28669993a(14) =31401775a(15) =39638108a(16) =2245196680a(17) =2878016306a(18) =5890364987a(19) =7838325300a(20) =23168759538a(21) =63226475740a(22) =121869542099
External references
- oeis: A229501