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A146768
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a(n) = numbers k such that 2(2^k)^2-1 = (n+1)-th Mersenne Prime = A000668(n+1)
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1
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1, 2, 3, 6, 8, 9, 15, 30, 44, 53, 63, 260, 303, 639, 1101, 1140, 1608, 2126, 2211, 4844, 4970, 5606, 9968, 10850, 11604, 22248, 43121, 55251, 66024, 108045, 378419, 429716, 628893, 699134, 1488110, 1510688, 3486296, 6733458, 10498005
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| The least common multiple of a even superperfect number greater than 2 and its arithmetic derivative divided itself, i.e., lcm(A061652(i), A061652(i)')/A061652(i). [Giorgio Balzarotti, Apr 21 2011]
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LINKS
| Helmes B., 9. Mersenne Numbers and the polynom f(x)=2x^2-1
George Woltman, Great Internet Mersenne Prime Search
C. K. Caldwell, Top 20 Mersenne primes
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FORMULA
| a(n) = (A000043(n+1)-1)/2
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CROSSREFS
| Sequence in context: A111215 A099381 A089437 * A122479 A047403 A093193
Adjacent sequences: A146765 A146766 A146767 * A146769 A146770 A146771
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KEYWORD
| nonn
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AUTHOR
| Artur Jasinski (grafix(AT)csl.pl), Nov 02 2008
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EXTENSIONS
| Added term for the 39th Mersenne prime. - Roderick(Roddy) MacPhee (science_man_88(AT)yahoo.com), Oct 05 2009
Formula and edits from Charles R Greathouse IV (charles.greathouse(AT)case.edu), Aug 14 2010
Updated to include 40th Mersenne prime. - Michael B. Porter (michael_b_porter(AT)yahoo.com), Nov 26 2010
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