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 A131634 n-th even semiprime minus n-th odd semiprime. 3
 -5, -9, -11, -11, -11, -9, -5, -11, -5, 3, 5, 9, 13, 9, 9, 19, 27, 29, 39, 31, 31, 39, 45, 55, 65, 69, 65, 71, 73, 71, 95, 101, 105, 101, 115, 117, 127, 125, 131, 141, 149, 149, 167, 169, 175, 177, 187, 209, 207, 209, 213, 219, 217, 235, 227, 237, 247, 247, 255, 261, 263, 281, 305, 303, 305, 311, 335, 345, 359, 359, 365, 363 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Starting with n=10, n-th even semiprime > n-th odd semiprime. Sequence is not monotonic, with general increasing trend. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 FORMULA a(n) = A100484(n) - A046315(n). MATHEMATICA Module[{semis=Select[Range[1000], PrimeOmega[#]==2&], ev, od, len}, ev = Select[ semis, EvenQ]; od=Select[semis, OddQ]; len=Min[Length[ ev], Length[ od]]; First[#]- Last[#]&/@Thread[{Take[ev, len], Take[od, len]}]] (* Harvey P. Dale, Apr 20 2014 *) CROSSREFS Cf. A046315, A100484. Sequence in context: A119124 A326769 A331005 * A049049 A118358 A101731 Adjacent sequences:  A131631 A131632 A131633 * A131635 A131636 A131637 KEYWORD sign,easy AUTHOR Zak Seidov, Oct 02 2007 STATUS approved

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Last modified February 20 11:52 EST 2020. Contains 332076 sequences. (Running on oeis4.)