A265526 Largest base-2 palindrome m <= n, written in base 2.
0, 1, 1, 11, 11, 101, 101, 111, 111, 1001, 1001, 1001, 1001, 1001, 1001, 1111, 1111, 10001, 10001, 10001, 10001, 10101, 10101, 10101, 10101, 10101, 10101, 11011, 11011, 11011, 11011, 11111, 11111, 100001, 100001, 100001, 100001, 100001, 100001, 100001, 100001, 100001, 100001, 100001, 100001, 101101, 101101, 101101
Offset: 0
Crossrefs
Programs
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Maple
ispal:= proc(n) global b; # test for base-b palindrome local L, Ln, i; L:= convert(n, base, b); Ln:= nops(L); for i from 1 to floor(Ln/2) do if L[i] <> L[Ln+1-i] then return(false); fi; od: return(true); end proc; # find max pal <= n, write in base 10 less10:=proc(n) global b; local t1,t2,i,m,sw1,L2; t1:=convert(n,base,b); for m from n by -1 to 0 do if ispal(m) then return(m); fi; od; end proc; # find max pal <= n, write in base b lessb:=proc(n) global b; local t1,t2,i,m,mb,sw1,L2; t1:=convert(n,base,b); for m from n by -1 to 0 do if ispal(m) then t2:=convert(m,base,b); L2:=nops(t2); mb:=add(t2[i]*10^(i-1), i=1..L2); return(mb); fi; od; end proc; b:=2; [seq(less10(n),n=0..100)]; # A206913 [seq(lessb(n),n=0..100)]; # A265526 [seq(less10(2*n),n=0..100)]; # A265527 [seq(lessb(2*n),n=0..100)]; # A265528 b:=10; [seq(less10(n),n=0..100)]; # A261423