A306361 - OEIS

%I #22 Nov 18 2019 16:44:00

%S 1,2,3,4,5,6,7,8,9,10,20,50,100,110,111,153,200,221,370,371,407,500,

%T 702,1000,1010,1011,1020,1100,1101,1110,1121,1122,1634,2000,2322,4104,

%U 5000,8208,9474,10000,10010,10011,10100,10101,10110,11000,11001,11010,11022,11100,11122,11220,12012,12110,12210,12320,14550

%N Numbers k divisible by A101337(k) (narcissistic function).

%C A005188 is a subsequence of this sequence.

%C Numbers in A007088 with either 3 or 9 ones are terms of this sequence. - _Chai Wah Wu_, Feb 26 2019

%C For all N in A007088 we have A101337(N) = A007953(N) = number of digits '1'; whenever this equals 2^k*5^m (k, m >= 0) and N ends in max(k,m) '0's, then N is also in this sequence. - _M. F. Hasler_, Nov 18 2019

%e For k = 20, 20 / (2^2 + 0^2) = 5;

%e for k = 221, 221 / (2^3 + 2^3 + 1^3) = 13.

%o (PARI) isok(n) = frac(n/A101337(n)) == 0; \\ _Michel Marcus_, Feb 11 2019

%o (PARI) select( is_A306361=t->!(t%A101337(t)), [0..9999]) \\ _M. F. Hasler_, Nov 18 2019

%Y Cf. A005188, A007088, A101337, A306354, A306360.

%K nonn,base

%O 1,2

%A _Ctibor O. Zizka_, Feb 10 2019