[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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