[seqfan] A December quiz with a non-prime array

Eric Angelini Eric.Angelini at kntv.be
Wed Dec 28 18:03:35 CET 2011


Hello Seqfans,
is it possible to put all non-primes in an array like
this one:
- every term is unique (and not prime)
- a term and his neighbor sum up on the line below.
Best,
É.
(hope no mistakes were left in the example below)

           1    8    4     14     6     10    22     27   15
             9    12   18      20    16    32     49   42
               21   30     38     36    48     81    91
                 51    68     74     84    129   301
                   119    142    158    213   301
                      261    300    371    514
                         561     671    885
                            1232    1556
                                2788

The array has been built by antidiagonals, choosing always
the smallest non-prime not yet in the array and not leading
to a contradiction.




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