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A203071
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Triangle read by antidiagonals: T[r+1,c] = T[r,c]+T[r,c+1], but only nonprime numbers may be used.
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2
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1, 8, 9, 4, 12, 21, 14, 18, 30, 51, 6, 20, 38, 68, 119, 10, 16, 36, 74, 142, 261, 22, 32, 48, 84, 158, 300, 561, 27, 49, 81, 129, 213, 371, 671, 1232, 15, 42, 91, 172, 301, 514, 885, 1556, 2788, 35, 50, 92, 183, 355, 656, 1170, 2055, 3611, 6399, 40, 75, 125, 217, 400, 755, 1411, 2581, 4636
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OFFSET
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1,2
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COMMENTS
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This sequence is the lexicographically earliest one satisfying the given constraint. It is built using the smallest possible choice for the next term [of the first row A203072] not leading to a contradiction.
Is this a permutation of the nonprimes?
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LINKS
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EXAMPLE
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row 1: 1 8 4 14 6 10 22 27 15 ... [A203072]
row 2: 9 12 18 20 16 32 49 42 ...
row 3: 21 30 38 36 48 81 91 ...
row 4: 51 68 74 84 129 172 ...
row 5: 119 142 158 213 301 ...
row 6: 261 300 371 514 ...
row 7: 561 671 885 ...
row 8: 1232 1556 ...
row 9: 2788 ...
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PROG
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(PARI) list_by_antidiagonals(a)={my(u=[]); for(i=1, #a, u=concat(u, a[i]); forstep(j=i-1, 1, -1, u=concat(u, a[j]+=a[j+1]))); u} /* requires the first line as input */
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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