cp's OEIS Frontend

A051247 Binary numbers d(1)...d(j) such that d(i) = d(j+1-i) for all but 4 values of i.

%I A051247 #14 Nov 10 2024 09:24:53
%S A051247 10,12,18,22,24,28,34,36,39,40,43,46,48,53,54,57,58,60,66,68,71,74,76,
%T A051247 79,80,83,86,88,91,94,96,101,102,104,109,110,113,114,116,121,122,124,
%U A051247 130,132,135,136,139,141,144,147,149,154,156
%N A051247 Binary numbers d(1)...d(j) such that d(i) = d(j+1-i) for all but 4 values of i.
%C A051247 Each number becomes a palindrome by changing two digits.
%H A051247 Robert Israel, <a href="/A051247/b051247.txt">Table of n, a(n) for n = 1..10000</a>
%p A051247 filter:= proc(n) local L;
%p A051247   L:= convert(n,base,2):
%p A051247   nops(select(i -> L[i] = L[-i], [$1..nops(L)]))=nops(L)-4
%p A051247 end proc:
%p A051247 select(filter, [$1..1000]); # _Robert Israel_, Nov 10 2024
%Y A051247 Cf. A051244, A050874.
%K A051247 nonn,base
%O A051247 1,1
%A A051247 _Clark Kimberling_
%E A051247 Name corrected by _Sean A. Irvine_, Aug 20 2021
%E A051247 Name corrected by _Robert Israel_, Nov 10 2024