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 A180169 Sigma(A180162(n)), where A180162(n) is the smallest N such that sigma(N) is an n-th power, or 0 if no such N can be found. 2
 1, 3, 4, 8, 1296, 32, 46656, 128, 256, 512, 1024, 362797056, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824, 2147483648 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Ray Chandler, Table of n, a(n) for n=1..469 FORMULA Empirical o.g.f.: (-1-1*x+2*x^2-1280*x^4+2560*x^5-46592*x^6+93184*x^7-362795008*x^11+725590016*x^12)/(2*x-1) Simon Plouffe, Feb. 26 2011. EXAMPLE A180162(4)=510 and so A180169(4)=sigma(510)=2^4*3^4. CROSSREFS Cf. A065496, A000203, A180162. Sequence in context: A096847 A011993 A286125 * A154714 A001695 A019676 Adjacent sequences:  A180166 A180167 A180168 * A180170 A180171 A180172 KEYWORD easy,nonn AUTHOR Walter Kehowski, Aug 14 2010 EXTENSIONS a(23) onwards from Ray Chandler, Aug 20 2010 STATUS approved

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