cp's OEIS Frontend

A331619 a(n) is the smallest positive number k such that the decimal expansion of n*2^k contains the string n.

%I A331619 #5 Jan 22 2020 12:57:28
%S A331619 1,4,4,7,4,9,4,8,4,10,10,10,10,10,10,10,10,7,10,10,4,10,10,10,10,10,
%T A331619 10,10,10,10,10,10,10,10,10,10,10,10,10,10,4,10,28,19,13,15,16,40,20,
%U A331619 30,53,27,20,27,35,30,20,53,31,20,4,8,18,35,20,10,30,23,20
%N A331619 a(n) is the smallest positive number k such that the decimal expansion of n*2^k contains the string n.
%H A331619 Rémy Sigrist, <a href="/A331619/a331619.gp.txt">PARI program for A331619</a>
%e A331619   n   a(n)  n*2^a(n)
%e A331619   --  ----  --------
%e A331619    0     1         0
%e A331619    1     4        16
%e A331619    2     4        32
%e A331619    3     7       384
%e A331619    4     4        64
%e A331619    5     9      2560
%e A331619    6     4        96
%e A331619    7     8      1792
%e A331619    8     4       128
%e A331619    9    10      9216
%e A331619   10    10     10240
%Y A331619 Cf. A030000, A331440.
%K A331619 nonn,base
%O A331619 0,2
%A A331619 _Rémy Sigrist_, Jan 22 2020