A158233 - OEIS

%I #6 Feb 03 2019 01:21:51

%S 6,4,3,0,3,6,0,3,0,0,4,0,0,4,6,0,0,6,0,6,0,0,6,3,0,3,6,3,4,0,0,4,0,0,

%T 4,0,0,6,3,0,3,6,0,0,3,0,0,6,0,6,0,0,3,3,6,4,0,0,4,0,0,4,0,0,4,3,0,3,

%U 0,0,0,3,0,6,6,0,3,6,0,3,0,0,0,3,0,6,6,0,3,0,0,4,0,0,4,0,0,4,0,0,4,0,0,4,6

%N a(n) = A120070(n+1)*A120070(n+2) mod 9.

%C Conjecture: this contains only the numbers 0,3,4,6 (verified for the first 5000 terms).

%C This multiply-modulo transformation is also used in the unrelated A157742, A158012, A158068, A158090.

%p A120070 := proc(m,n) if m-1 >= n then m^2-n^2; else 0; fi; end:

%p A120070flat := proc(n) i := 2 ; for m from 2 do for l from 1 to m-1 do if i = n then RETURN(A120070(m,l)) ; else i := i+1 ; fi; od: od: end:

%p A158233 := proc(n) (A120070flat(n+1)*A120070flat(n+2) ) mod 9 ; end: seq(A158233(n),n=1..180) ; # _R. J. Mathar_, Apr 09 2009

%K nonn

%O 1,1

%A _Paul Curtz_, Mar 14 2009

%E Edited and extended by _R. J. Mathar_, Apr 09 2009