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A007461 Shifts left under AND-convolution with itself.
(Formerly M0117)
7
1, 1, 2, 1, 2, 4, 0, 5, 2, 4, 0, 10, 0, 12, 4, 13, 6, 12, 0, 18, 12, 20, 20, 36, 20, 36, 16, 44, 32, 60, 40, 73, 50, 56, 40, 58, 44, 52, 60, 84, 36, 112, 88, 108, 136, 132, 152, 178, 136, 232, 108, 260, 244, 256, 304, 288 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
a(A000225(n)) mod 2 = 1, a(A062289(n)) mod 2 = 0. [Reinhard Zumkeller, Apr 02 2012]
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
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]
MAPLE
a:= proc(n) option remember; `if`(n=0, 1, add(
Bits[And](a(i), a(n-1-i)), i=0..n-1))
end:
seq(a(n), n=0..80); # Alois P. Heinz, Jun 16 2018
MATHEMATICA
a[0]=1; a[1]=1; a[n_] := a[n] = Sum[BitAnd[a[k], a[n-k-1]], {k, 0, n-1}]; Table[a[n], {n, 0, 60}] (* Jean-François Alcover, Sep 07 2012 *)
PROG
(Haskell)
import Data.Bits ((.&.))
a007461 n = a007461_list !! n
a007461_list = 1 : f [1, 1] where
f xs = x : f (x:xs) where
x = sum $ zipWith (.&.) xs $ tail $ reverse xs :: Integer
-- Reinhard Zumkeller, Apr 02 2012
CROSSREFS
Sequence in context: A265255 A131022 A137408 * A181302 A304785 A143446
KEYWORD
nonn,nice,eigen
AUTHOR
STATUS
approved

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Last modified March 19 04:58 EDT 2024. Contains 370952 sequences. (Running on oeis4.)