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A007460 Shifts left under OR-convolution with itself.

%I A007460 M1752 #33 Jun 16 2018 18:01:21
%S A007460 1,1,2,7,20,58,174,519,1550,4634,13884,41616,124824,374390,1123288,
%T A007460 3369297,10107324,30320434,90961626,272878138,818632094,2455888346,
%U A007460 7367661682,22102935920,66308767426,198926187730,596778527246,1790335274112,5371006016314
%N A007460 Shifts left under OR-convolution with itself.
%D A007460 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A007460 Alois P. Heinz, <a href="/A007460/b007460.txt">Table of n, a(n) for n = 0..2097</a>
%H A007460 M. Bernstein and N. J. A. Sloane, <a href="http://arXiv.org/abs/math.CO/0205301">Some canonical sequences of integers</a>, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to arXiv version]
%H A007460 M. Bernstein and N. J. A. Sloane, <a href="/A003633/a003633_1.pdf">Some canonical sequences of integers</a>, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to Lin. Alg. Applic. version together with omitted figures]
%F A007460 a(n) ~ c * 3^n, where c = 0.23477965293553321256228091184896942343087043274059369777596946751928557... . - _Vaclav Kotesovec_, Sep 11 2014
%p A007460 a:= proc(n) option remember; `if`(n=0, 1, add(
%p A007460       Bits[Or](a(i), a(n-1-i)), i=0..n-1))
%p A007460     end:
%p A007460 seq(a(n), n=0..35);  # _Alois P. Heinz_, Jun 22 2012, revised, Jun 16 2018
%t A007460 a[0]=1; a[1]=1; a[n_] := a[n] = Sum[BitOr[a[k], a[n-k-1]], {k, 0, n-1}]; Table[a[n], {n, 0, 30}] (* _Jean-François Alcover_, Sep 07 2012, after _Alois P. Heinz_ *)
%o A007460 (Haskell)
%o A007460 import Data.Bits ((.|.))
%o A007460 a007460 n = a007460_list !! n
%o A007460 a007460_list = 1 : f [1,1] where
%o A007460    f xs = x : f (x:xs) where
%o A007460      x = sum $ zipWith (.|.) xs $ tail $ reverse xs :: Integer
%o A007460 -- _Reinhard Zumkeller_, Dec 29 2012
%K A007460 nonn,nice,eigen
%O A007460 0,3
%A A007460 _N. J. A. Sloane_