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A338820
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a(n) = Sum_{i=1..n-1} (prime(i)^2 mod prime(n)).
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3
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0, 1, 8, 10, 21, 39, 54, 58, 61, 135, 134, 213, 217, 259, 267, 449, 413, 530, 645, 471, 661, 734, 741, 1029, 1194, 1257, 1219, 1434, 1372, 1456, 1547, 1939, 2007, 1987, 2471, 2319, 2802, 2610, 2564, 3334, 3548, 3684, 3612, 3576, 4399, 3686, 5071, 4810, 4647, 5066, 6035, 5213, 5890, 6335, 6327
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OFFSET
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1,3
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COMMENTS
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The sequence is not monotone, and not one-to-one: a(95)=a(97)=23038.
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LINKS
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EXAMPLE
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The first three primes are 2, 3, 5, so a(3) = (2^2 mod 5) + (3^2 mod 5) = 4 + 4 = 8.
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MAPLE
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P:= [seq(ithprime(i), i=1..100)]:
seq(add(P[i]^2 mod P[n], i=1..n-1), n=1..100);
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PROG
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(PARI) a(n) = my(p=prime(n)); sum(i=1, n-1, lift(Mod(prime(i), p)^2)); \\ Michel Marcus, Nov 11 2020
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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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