A158233 a(n) = A120070(n+1)*A120070(n+2) mod 9.

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, 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, 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

Offset: 1

Author

Paul Curtz, Mar 14 2009

Keywords

• nonn

Comments

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

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

Programs

Maple

A120070 := proc(m,n) if m-1 >= n then m^2-n^2; else 0; fi; end:
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:
A158233 := proc(n) (A120070flat(n+1)*A120070flat(n+2) ) mod 9 ; end: seq(A158233(n),n=1..180) ; # R. J. Mathar, Apr 09 2009

Extensions

Edited and extended by R. J. Mathar, Apr 09 2009