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A034094
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(-1)sigma perfect numbers: (-1)sigma(a) = m*a for some integer m, where if a = Product p(i)^r(i) then (-1)sigma(a) = Product (-1+Sum p(i)^s(i), s(i)=1 to r(i)).
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3
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20, 312, 9744, 29280, 53352, 1666224, 5006880, 106798080, 980733600, 133301760, 9099742080, 22794600960, 1556055895680, 3577201689600, 4464942451200, 380428773854896765462278360268800000
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The indices of some terms are 1, so these numbers are fixed points of (-1)sigma.
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EXAMPLE
| Factorizations 2^2*5, 2^3*3*13, 2^4*3*7*29, 2^5*3*5*61, 2^3*3^3*13*19, 2^4*3^3*7*19*29, 2^5*3^3*5*19*61, 2^10*3*5*17*409, 2^5*3^2*5^2*7*11*29*61, 2^9*3*5*17*1021, 2^7*3*5*11^2*13*23*131, 2^9*3^3*5*17*19*1021, 2^7*3^3*5*11^2*13*19*23*131, 2^10*3^2*5^2*7*11*17*29*409, 2^9*3^2*5^2*7*11*17*29*1021, 2^24*3^3*5^5*7^2*11*17*19*29*61*233*239*467*479*70051
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CROSSREFS
| Cf. A034095, A049060.
Sequence in context: A016190 A016188 A006300 * A011197 A054621 A111778
Adjacent sequences: A034091 A034092 A034093 * A034095 A034096 A034097
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KEYWORD
| nonn
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AUTHOR
| Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp)
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