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A261678
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Even numbers that are not the sum of two binary palindromes.
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8
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176, 188, 208, 242, 244, 310, 524, 628, 656, 736, 754, 794, 832, 862, 866, 868, 880, 932, 944, 994, 1000, 1180, 1240, 1308, 1310, 1328, 1342, 1352, 1376, 1408, 1420, 1432, 1440, 1810, 1890, 1922, 1946, 1954, 2126, 2206, 2228, 2262, 2456, 2468, 2498, 2500
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OFFSET
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1,1
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COMMENTS
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Even numbers that are not the sum of two terms from A006995.
A subsequence of the numbers that are not the sum of three terms from A006995. The two sequences are equal if every odd number is the sum of three terms from A006995 (which is equivalent to the conjecture in A261680). - Chai Wah Wu, Sep 14 2015
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LINKS
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MAPLE
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R:=proc(w) local x, y, z; x:=w; y:=0; for z from 1 to ilog10(x)+1 do y:=10*y+(x mod 10); x:=trunc(x/10); od; y; end:
P:=proc(q) local a, b, k, n, ok; n:=2*q; ok:=1; for k from 1 to trunc(n/2) do a:=convert(k, binary, decimal); b:=convert(n-k, binary, decimal);
if a=R(a) and b=R(b) then ok:=0; break; fi; od; if ok=1 then n; fi; end: seq(P(i), i=1..1250); # Paolo P. Lava, Aug 03 2017
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MATHEMATICA
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lim = 2502; Complement[Most[2 Range@(lim/2)], TakeWhile[DeleteDuplicates@
Sort[Total /@ Tuples[Select[Range@ lim, palQ[#, 2] &], 2]], # < lim &]] (* Michael De Vlieger, Sep 14 2015 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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