A171868 - OEIS

%I #16 Jul 19 2020 11:53:30

%S 1,2,2,5,2,5,3,4,6,5,6,3,3,5,4,3,4,3,6,9,3,5,3,6,3,4,5,6,5,4,4,5,4,4,

%T 6,4,4,6,6,5,6,4,4,9,3,3,6,4,3,10,3,4,4,6,4,5,3,3,6,6,7,3,5,4,5,4,6,6,

%U 6,5,4,6,4,4,6,4,5,4,7,3,4,5,4,8,10,3,5,5,6,3,8,4,4,6,7,6,6,10,4,4,8,3,4,4

%N First differences of A171865.

%H N. J. A. Sloane, <a href="/A171868/b171868.txt">Table of n, a(n) for n = 1..15098</a>

%o (Haskell)

%o a171868 n = a171868_list !! (n-1)

%o a171868_list = zipWith (-) (tail a171865_list) a171865_list

%o -- _Reinhard Zumkeller_, Oct 31 2011

%o (Python)

%o A181391_list, A171868_list, l = [0, 0], [1], 0

%o for n in range(1, 10**4):

%o ....for m in range(n-1, -1, -1):

%o ........if A181391_list[m] == A181391_list[n]:

%o ............A181391_list.append(n-m)

%o ............break

%o ....else:

%o ........A181391_list.append(0)

%o ........A171868_list.append(n-l)

%o ........l = n # _Chai Wah Wu_, Jan 02 2015

%Y Cf. A181391, A171865, A171888, A171887.

%Y Identical to A171889 except for the leading 0. - Jan Ritsema van Eck (j.ritsemavaneck(AT)planet.nl), Oct 19 2010

%K nonn

%O 1,2

%A _N. J. A. Sloane_, Oct 18 2010