A078220 - OEIS

%I #6 Apr 11 2021 16:13:32

%S 4,7,1,13,16,2,23,26,3,32,36,4,42,45,5,51,55,6,61,64,7,71,74,77,8,83,

%T 86,9,93,96,10,102,106,11,112,115,12,121,125,13,131,134,14,141,144,

%U 147,15,153,156,16,163,166,17,172,176,18,182,185,19,191,195,20,201,204,21,211

%N Smallest k such that floor(k*Pi) begins with n (Pi=3.14159...).

%e a(4) = 13 as floor(13*Pi) = 40 while floor(12*Pi) = 37.

%p C := Pi; a := proc(M0,M,C) local i,d,f,g,k; description "returns the sequence 'a(n)' between 'M0' and 'M' where 'a(n)=min{k | floor(C*k) begins with n}."; d := N->`if`(N=0,[0],ListTools[Reverse](convert(N,base,10))); f := (K,N)->`if`(d(floor(K*C))[1..min(nops(d(floor(K*C))),nops(d(N)))]=d(N),K,0); for i from M0 to M do k := 0; while f(k,i)=0 do k := k+1; od; g(i) := f(k,i) od; return seq(g(j),j=M0..M); end proc;

%K base,nonn

%O 1,1

%A _Amarnath Murthy_, Nov 22 2002

%E More terms from Francois Jooste (pin(AT)myway.com), Mar 10 2003