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 A101757 Indices of semiprime tribonacci numbers. 1
 5, 12, 18, 42, 44, 50, 58, 67, 74, 83, 90, 95, 126, 142, 194, 210, 211, 275, 367, 382, 479, 655, 734, 818, 839, 926, 939, 1047 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Eric Weisstein's World of Mathematics, Semiprime Eric Weisstein's World of Mathematics, Tribonacci Number Index entries for linear recurrences with constant coefficients, signature (1, 1, 1). FORMULA A000073(a(n)) = A101758(n). MATHEMATICA Flatten[Position[LinearRecurrence[{1, 1, 1}, {1, 1, 2}, 100], _?(PrimeOmega[ #]==2&)]]+1 (* This generates the first 12 terms of the sequence.  To generate more, increase 100 to a higher number, but it will take increasingly long to run. *) (* Harvey P. Dale, May 31 2013 *) CROSSREFS Cf. A000073, A001358, A101758. Sequence in context: A314290 A246300 A294143 * A174518 A109403 A093084 Adjacent sequences:  A101754 A101755 A101756 * A101758 A101759 A101760 KEYWORD nonn,more AUTHOR Jonathan Vos Post and Ray Chandler, Dec 26 2004 EXTENSIONS More terms from David Wasserman, Apr 03 2008 STATUS approved

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Last modified May 25 03:14 EDT 2019. Contains 323539 sequences. (Running on oeis4.)