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A216765
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Perfect powers (squares, cubes, etc.) plus 1.
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5
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5, 9, 10, 17, 26, 28, 33, 37, 50, 65, 82, 101, 122, 126, 129, 145, 170, 197, 217, 226, 244, 257, 290, 325, 344, 362, 401, 442, 485, 513, 530, 577, 626, 677, 730, 785, 842, 901, 962, 1001, 1025, 1090, 1157, 1226, 1297, 1332, 1370, 1445, 1522, 1601, 1682, 1729, 1765
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OFFSET
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1,1
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COMMENTS
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Integers of the form m^k + 1 for integers m, k >= 2.
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REFERENCES
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Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 2.6, p. 113.
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LINKS
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FORMULA
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Sum_{n>=1} 1/a(n) = Pi^2/3 - 5/2 (Lev, 2002). - Amiram Eldar, Oct 15 2020
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EXAMPLE
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a(1) = 2^2 + 1; a(2) = 2^3 + 1; a(3) = 3^2 + 1; a(4) = 2^4 + 1.
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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