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 A050605 Column/row 2 of A050602: a(n) = add3c(n,2). 5
 0, 0, 1, 1, 0, 0, 2, 2, 0, 0, 1, 1, 0, 0, 3, 3, 0, 0, 1, 1, 0, 0, 2, 2, 0, 0, 1, 1, 0, 0, 4, 4, 0, 0, 1, 1, 0, 0, 2, 2, 0, 0, 1, 1, 0, 0, 3, 3, 0, 0, 1, 1, 0, 0, 2, 2, 0, 0, 1, 1, 0, 0, 5, 5, 0, 0, 1, 1, 0, 0, 2, 2, 0, 0, 1, 1, 0, 0, 3, 3, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,7 COMMENTS It seems that (n - Sum_{k=1..n} a(k) )/log(n) is bounded. - Benoit Cloitre, Oct 03 2002 2^a(n) is the highest power of 2 dividing the n-th triangular number n*(n+1)/2. - Benoit Cloitre, Oct 03 2002 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..5000 MAPLE nmax:=80; with(Bits): add3c := proc(a, b) option remember; if(0 = And(a, b)) then RETURN(0); else RETURN(1+add3c(Xor(a, b), 2*And(a, b))); fi; end: for n from 0 to nmax do a(n):=add3c(n, 2) od: seq(a(n), n=0..nmax); # Johannes W. Meijer, Jun 18 2009 MATHEMATICA Table[IntegerExponent[(n + 1)(n + 2)/2, 2], {n, 0, 100}] (* Jean-François Alcover, Mar 04 2016 *) PROG (PARI) a(n)=valuation(n*(n+1)/2, 2) (MAGMA) [Valuation(n*(n+1)/2, 2): n in [1..120]]; // Vincenzo Librandi, Aug 11 2017 CROSSREFS Bisection gives column/row 1 of A050602: A007814. From Johannes W. Meijer, Jun 18 2009: (Start) a(4*n+2) = A001511(n). Cf. A161737 and A069834. (End) Sequence in context: A295520 A295335 A227838 * A060571 A131555 A293209 Adjacent sequences:  A050602 A050603 A050604 * A050606 A050607 A050608 KEYWORD nonn AUTHOR Antti Karttunen, Jun 22 1999 STATUS approved

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Last modified January 19 21:52 EST 2019. Contains 319310 sequences. (Running on oeis4.)