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A178155
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Partial sums of A003407 (starting at n=1).
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0
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1, 3, 7, 17, 37, 85, 189, 471, 967, 2033, 4493, 10621, 23461, 52841, 127745, 340473, 708489, 1367785, 2738841, 5675977, 12313209, 27929825, 66361381, 162909213, 361319381, 780460693, 1722272781, 3904263759, 9528920767, 24294326763, 66213009251, 187941084483, 395937137667, 756194730883, 1395731222259, 2540709556499, 4903320997075, 9814465115099
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OFFSET
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1,2
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COMMENTS
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Partial sums of number of permutations with no 3-term arithmetic progression. The subsequence of primes in this partial sum begins with 4 in a row: 3, 7, 17, 37, 967, 4493, 66361381, 780460693, 9814465115099, 1094158908254653, ...
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LINKS
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FORMULA
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EXAMPLE
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a(11) = 1 + 2 + 4 + 10 + 20 + 48 + 104 + 282 + 496 + 1066 + 2460 = 4493 is prime.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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