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A011756
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a(n) = prime(n(n+1)/2).
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10
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2, 5, 13, 29, 47, 73, 107, 151, 197, 257, 317, 397, 467, 571, 659, 769, 883, 1019, 1151, 1291, 1453, 1607, 1783, 1987, 2153, 2371, 2593, 2791, 3037, 3307, 3541, 3797, 4073, 4357, 4657, 4973, 5303, 5641, 5939, 6301, 6679, 7019, 7477
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OFFSET
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1,1
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COMMENTS
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There are n distinct successive primes p (not appearing in the sequence) such that a(n) < p < a(n+1). - David James Sycamore, Jul 22 2018
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LINKS
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FORMULA
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a(n) is asymptotic to (n*(n+1)/2) * log(n*(n+1)/2) = (n*(n+1)/2) * (log(n)+log(n+1)-log(2)) ~ (n^2 + n)*(2 log n)/2 ~ (n^2 + n)*(log n). - Jonathan Vos Post, Mar 12 2006
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MAPLE
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MATHEMATICA
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PROG
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(Haskell)
a011756 n = a011756_list !! (n-1)
a011756_list = map a000040 $ tail a000217_list
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CROSSREFS
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Primes in leading diagonal of triangle in A078721.
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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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