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 A241491 2*n is not the sum of two base-2 palindromes 7
 88, 94, 104, 121, 122, 155, 262, 314, 328, 368, 377, 397, 416, 431, 433, 434, 440, 466, 472, 497, 500, 590, 620, 654, 655, 664, 671, 676, 688, 704, 710, 716, 720, 905, 945, 961, 973, 977, 1063, 1103, 1114, 1131, 1228, 1234, 1249, 1250, 1270, 1312, 1343, 1348 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Note that since all nonzero base-2 palindromes are odd, the sum of two nonzero base-2 palindromes is even. LINKS Robert Israel, Table of n, a(n) for n = 1..10000 EXAMPLE 86 is not in the sequence because 2*86 = 7 + 165, and 7 and 165 are in A006995. MAPLE N:= 15; # for all entries up to 2^(N-1) with(SignalProcessing): # requires Maple 17+ rev2:= proc(n) option remember;   rev2(floor(n/2)) + (n mod 2)*2^ilog2(n) end; rev2(0) := 0; rev2(1):= 1; B:= Array(1..2^N, datatype=float[8]); for d from 1 to N do   d1:= ceil(d/2);   for x from 2^(d1-1) to 2^d1-1 do     if d::even then y:= x*2^d1+rev2(x)     else y:= x*2^(d1-1)+rev2(floor(x/2));     fi;   B[y]:= 1; od od: B2:= Convolution(B, B); A241491:= select(t -> B2[2*t-1] < 0.5, [\$1..2^(N-1)]); # Robert Israel, Apr 24 2014 CROSSREFS Cf. A006995, A261678 (values of 2n). Sequence in context: A147317 A143846 A255226 * A068356 A215830 A216873 Adjacent sequences:  A241488 A241489 A241490 * A241492 A241493 A241494 KEYWORD nonn,base AUTHOR Robert Israel, Apr 24 2014 STATUS approved

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Last modified June 29 17:41 EDT 2022. Contains 354913 sequences. (Running on oeis4.)