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 A230091 Numbers of the form k + wt(k) for exactly two distinct k, where wt(k) = A000120(k) is the binary weight of k. 10
 5, 14, 17, 19, 22, 31, 33, 36, 38, 47, 50, 52, 55, 64, 67, 70, 79, 82, 84, 87, 96, 98, 101, 103, 112, 115, 117, 120, 131, 132, 143, 146, 148, 151, 160, 162, 165, 167, 176, 179, 181, 184, 193, 196, 199, 208, 211, 213, 216, 225, 227, 230, 232, 241, 244, 246, 249, 258, 260, 262, 271, 274, 276, 279, 288, 290, 293, 295 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The positions of entries equal to 2 in A228085, or numbers that appear exactly twice in A092391. Numbers that can be expressed as the sum of distinct terms of the form 2^n+1, n=0,1,... in exactly two ways. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 EXAMPLE 5 = 3 + 2 = 4 + 1, so 5 is in this list. MAPLE # Maple code for A000120, A092391, A228085, A010061, A228088, A230091, A230092 with(LinearAlgebra): read transforms; wt := proc(n) local w, m, i; w := 0; m := n; while m > 0 do i := m mod 2; w := w+i; m := (m-i)/2; od; w; end: # A000120 M:=1000; lis1:=Array(0..M); lis2:=Array(0..M); ctmax:=4; for i from 0 to ctmax do ct[i]:=Array(0..M); od: for n from 0 to M do m:=n+wt(n); lis1[n]:=m; if (m <= M) then lis2[m]:=lis2[m]+1; fi; od: t1:=[seq(lis1[i], i=0..M)]; # A092391 t2:=[seq(lis2[i], i=0..M)]; # A228085 COMPl(t1); # A010061 for i from 1 to M do h:=lis2[i]; if h <= ctmax then ct[h]:=[op(ct[h]), i]; fi; od: len:=nops(ct[0]); [seq(ct[0][i], i=1..len)]; # A010061 again len:=nops(ct[1]); [seq(ct[1][i], i=1..len)]; # A228088 len:=nops(ct[2]); [seq(ct[2][i], i=1..len)]; # A230091 len:=nops(ct[3]); [seq(ct[3][i], i=1..len)]; # A230092 PROG (Haskell) a230091 n = a230091_list !! (n-1) a230091_list = filter ((== 2) . a228085) [1..] -- Reinhard Zumkeller, Oct 13 2013 CROSSREFS Cf. A000120, A010061, A092391, A228088, A228085, A230058, A230092. Cf. A227915. Sequence in context: A196366 A306772 A230058 * A053782 A296692 A102884 Adjacent sequences:  A230088 A230089 A230090 * A230092 A230093 A230094 KEYWORD nonn,base AUTHOR N. J. A. Sloane, Oct 10 2013 STATUS approved

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Last modified September 16 09:01 EDT 2019. Contains 327093 sequences. (Running on oeis4.)