login
a(n) = smallest k such that 2k has digit sum = n.
2

%I #9 Sep 15 2020 20:48:22

%S 5,1,6,2,7,3,8,4,9,14,19,24,29,34,39,44,49,99,149,199,249,299,349,399,

%T 449,499,999,1499,1999,2499,2999,3499,3999,4499,4999,9999,14999,19999,

%U 24999,29999,34999,39999,44999,49999,99999,149999,199999,249999,299999

%N a(n) = smallest k such that 2k has digit sum = n.

%H <a href="/index/Rec#order_10">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,0,0,0,10,-10).

%F a(n) = A069532(n)/2.

%Y Cf. A069532, A069534.

%K base,nonn,easy

%O 1,1

%A _Amarnath Murthy_, Nov 07 2002

%E More terms from _Ray Chandler_, Jul 28 2003