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%I M1752 #33 Jun 16 2018 18:01:21
%S 1,1,2,7,20,58,174,519,1550,4634,13884,41616,124824,374390,1123288,
%T 3369297,10107324,30320434,90961626,272878138,818632094,2455888346,
%U 7367661682,22102935920,66308767426,198926187730,596778527246,1790335274112,5371006016314
%N Shifts left under OR-convolution with itself.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H Alois P. Heinz, <a href="/A007460/b007460.txt">Table of n, a(n) for n = 0..2097</a>
%H 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 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 a(n) ~ c * 3^n, where c = 0.23477965293553321256228091184896942343087043274059369777596946751928557... . - _Vaclav Kotesovec_, Sep 11 2014
%p a:= proc(n) option remember; `if`(n=0, 1, add(
%p Bits[Or](a(i), a(n-1-i)), i=0..n-1))
%p end:
%p seq(a(n), n=0..35); # _Alois P. Heinz_, Jun 22 2012, revised, Jun 16 2018
%t 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 (Haskell)
%o import Data.Bits ((.|.))
%o a007460 n = a007460_list !! n
%o a007460_list = 1 : f [1,1] where
%o f xs = x : f (x:xs) where
%o x = sum $ zipWith (.|.) xs $ tail $ reverse xs :: Integer
%o -- _Reinhard Zumkeller_, Dec 29 2012
%K nonn,nice,eigen
%O 0,3
%A _N. J. A. Sloane_
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