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A105090
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Sum of the left diagonal in ordered 3 X 3 prime squares.
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0
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36, 133, 253, 389, 533, 679, 841, 1007, 1175, 1327, 1489, 1703, 1859, 2021, 2209, 2405, 2571, 2769, 2977, 3139, 3319, 3545, 3733, 3905, 4135, 4361, 4525, 4721, 4891, 5099, 5319, 5549, 5743, 5987, 6177, 6361, 6599, 6813, 7021, 7193, 7425, 7675, 7927
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OFFSET
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1,1
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LINKS
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FORMULA
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An ordered 3 X 3 prime square is 9 consecutive primes arranged in a square of the form p(9n-8) p(9n-7) p(9n-6) p(9n-5) p(9n-4) p(9n-3) p(9n-2) p(9n-1) p(9n) n=1, 2, .. Left diagonal is p(9n-8) p(9n-4) p(9n)
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EXAMPLE
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The first 3 X 3 prime square
2 3 5
7 11 13
17 19 23
sum of left diagonal = 2 + 11 + 23 = 36 the first entry.
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PROG
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(PARI) sum3x3left(n) = { local(x, j, s); forstep(x=0, n, 9, s=0; forstep(j=1, 9, 4, s += prime(x+j); ); print1(s", ") ) }
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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