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A007460 Shifts left under OR-convolution with itself.
(Formerly M1752)
7
1, 1, 2, 7, 20, 58, 174, 519, 1550, 4634, 13884, 41616, 124824, 374390, 1123288, 3369297, 10107324, 30320434, 90961626, 272878138, 818632094, 2455888346, 7367661682, 22102935920, 66308767426, 198926187730, 596778527246, 1790335274112, 5371006016314 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..600

M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to arXiv version]

M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to Lin. Alg. Applic. version together with omitted figures]

FORMULA

a(n) ~ c * 3^n, where c = 0.23477965293553321256228091184896942343087043274059369777596946751928557... . - Vaclav Kotesovec, Sep 11 2014

MAPLE

OR:= proc(n, k) local m, l, i, r;

       m, l, r:= n, k, 0;

       for i from 0 while m>0 or l>0 do

         r:= r +2^i* max(irem(m, 2, 'm'), irem(l, 2, 'l'))

       od; r;

     end:

a:= proc(n) option remember;

      `if`(n=0, 1, add(OR(a(i), a(n-1-i)), i=0..n-1))

    end:

seq(a(n), n=0..30);  # Alois P. Heinz, Jun 22 2012

MATHEMATICA

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-Fran├žois Alcover, Sep 07 2012, after Alois P. Heinz *)

PROG

(Haskell)

import Data.Bits ((.|.))

a007460 n = a007460_list !! n

a007460_list = 1 : f [1, 1] where

   f xs = x : f (x:xs) where

     x = sum $ zipWith (.|.) xs $ tail $ reverse xs :: Integer

-- Reinhard Zumkeller, Dec 29 2012

CROSSREFS

Sequence in context: A049681 A027120 A094982 * A034899 A026124 A026153

Adjacent sequences:  A007457 A007458 A007459 * A007461 A007462 A007463

KEYWORD

nonn,nice,eigen

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified July 22 03:22 EDT 2017. Contains 289648 sequences.