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 A123728 Call (m,n) a "(-1)SSU amicable pair" if (-1)Sigma(m)*Sigma(m) = k*UnitaryPhi(m)*(m+n) and (-1)Sigma(n)*Sigma(n) = k*UnitaryPhi(n)*(m+n) for some integer k. Sequence gives values of m, assuming n <= m. 2
 6, 140, 1316, 1560, 14384, 18018, 23562, 40992, 94188, 141128, 168730, 187652 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(3) is an example with m != n. R. J. Mathar did an exhaustive search up to 2000. Giovanni Resta searched up to 10^7. LINKS EXAMPLE Kohmoto found the following terms. k=3: m=2^9*3*31*1021*7*23 n=2^9*3*31*1021*191 m=2^5*3*61*5*11 n=2^5*3*61*71 m=2^8*7*37*73*509*3*5 n=2^8*7*37*73*509*23 m=2^8*7*19*37*73*509*3*11 n=2^8*7*19*37*73*509*47 m=2^8*5*7*37*73*509*11*59 n=2^8*5*7*37*73*509*719 k=2: m=2*3^2*5*13*23*29 n=2*3^2*5*13*719 m=2^2*7*3*11 n=2^2*7*47 m=3^2*5^2*13*29*17*19 n=3^2*5^2*13*29*359 k=5: m=2^5*3^2*7*13*61*23*29 n=2^5*3^2*7*13*61*719 m=2^9*3^2*11*13*31*1021*23*29 n=2^9*3^2*11*13*31*1021*719 CROSSREFS Cf. A123729 (values of n), A123582 (values of k). Sequence in context: A335388 A123729 A193835 * A193876 A293124 A193185 Adjacent sequences: A123725 A123726 A123727 * A123729 A123730 A123731 KEYWORD nonn,more AUTHOR Yasutoshi Kohmoto, Nov 18 2006 STATUS approved

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Last modified February 3 14:36 EST 2023. Contains 360035 sequences. (Running on oeis4.)