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 A259162 Positive hexagonal numbers (A000384) that are pentagonal numbers (A000326) divided by 2. 3
 6, 58311, 559902916, 5376187741821, 51622154137063026, 495675918647891434531, 4759480119234899417304336, 45700527609217585557064800441, 438816461344227137284036796530846, 4213515616126741362983735763224383551, 40458176507232509223142693514443734326556 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Intersection of A000384 and A193866 (even pentagonal numbers divided by 2). - Michel Marcus, Jun 20 2015 LINKS Colin Barker, Table of n, a(n) for n = 1..251 Index entries for linear recurrences with constant coefficients, signature (9603,-9603,1). FORMULA G.f.: -x*(x^2+693*x+6) / ((x-1)*(x^2-9602*x+1)). EXAMPLE 6 is in the sequence because 6 is the 2nd hexagonal number, and 2*6 is the 3rd pentagonal number. MATHEMATICA LinearRecurrence[{9603, -9603, 1}, {6, 58311, 559902916}, 20] (* Vincenzo Librandi, Jun 20 2015 *) PROG (PARI) Vec(-x*(x^2+693*x+6)/((x-1)*(x^2-9602*x+1)) + O(x^20)) CROSSREFS Cf. A000326, A000384, A193866, A259156-A259161, A259163-A259167. Sequence in context: A295817 A118859 A323725 * A076913 A101450 A101439 Adjacent sequences: A259159 A259160 A259161 * A259163 A259164 A259165 KEYWORD nonn,easy AUTHOR Colin Barker, Jun 19 2015 STATUS approved

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Last modified December 5 05:37 EST 2023. Contains 367575 sequences. (Running on oeis4.)