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 A050601 Recursion counts for summation table A003056 with formula a(0,x) = x, a(y,0) = y, a(y,x) = a((y XOR x),2*(y AND x)) 2
 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 2, 1, 2, 0, 0, 1, 2, 2, 1, 0, 0, 2, 1, 1, 1, 2, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 3, 2, 3, 1, 3, 2, 3, 0, 0, 1, 3, 3, 2, 2, 3, 3, 1, 0, 0, 2, 1, 3, 2, 1, 2, 3, 1, 2, 0, 0, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 0, 0, 3, 2, 3, 1, 3, 1, 3, 1, 3, 2, 3, 0, 0, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 0, 0, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 0 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,12 LINKS FORMULA a(n) -> add2c( (n-((trinv(n)*(trinv(n)-1))/2)), (((trinv(n)-1)*(((1/2)*trinv(n))+1))-n) ) MAPLE add2c := proc(a, b) option remember; if((0 = a) or (0 = b)) then RETURN(0); else RETURN(1+add_c(XORnos(a, b), 2*ANDnos(a, b))); fi; end; MATHEMATICA trinv[n_] := Floor[(1/2)*(Sqrt[8*n + 1] + 1)]; Sum2c[a_, b_] := Sum2c[a, b] = If[0 == a || 0 == b, Return[0], Return[ Sum2c[BitXor[a, b], 2*BitAnd[a, b]] + 1]]; a[n_] := Sum2c[n - (1/2)*trinv[n]*(trinv[n] - 1), (trinv[n] - 1)*(trinv[ n]/2 + 1) - n]; Table[a[n], {n, 0, 120}](* Jean-François Alcover, Mar 07 2016, adapted from Maple *) CROSSREFS Cf. A050600, A050602, A003056, A048720 (for the Maple implementation of trinv and XORnos, ANDnos) Sequence in context: A101664 A091952 A108803 * A101650 A287411 A053796 Adjacent sequences:  A050598 A050599 A050600 * A050602 A050603 A050604 KEYWORD nonn,tabl AUTHOR Antti Karttunen, Jun 22 1999 STATUS approved

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Last modified February 22 23:02 EST 2020. Contains 332157 sequences. (Running on oeis4.)