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 A111329 Number of partitions of T where T = (3n + 1) if n is even and T=(3n + 1)/2 if n is odd. 3
 2, 15, 7, 101, 22, 490, 56, 1958, 135, 6842, 297, 21637, 627, 63261, 1255, 173525, 2436, 451276, 4565, 1121505, 8349, 2679689, 14883, 6185689, 26015, 13848650, 44583, 30167357, 75175, 64112359, 124754, 133230930, 204226, 271248950, 329931 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Jeffrey C. Lagarias The 3x+1 problem: An annotated bibliography arXiv:math/0309224 [math.NT], 2003-2011. Jeffrey C. Lagarias, "The Problem and Its Generalizations." Amer. Math. Monthly 92, 3-23, 1985. Eric Weisstein's World of Mathematics, Collatz Problem FORMULA a(n) = A000041(A165355(n-1)). [Reinhard Zumkeller, Nov 19 2009] EXAMPLE If n=1 then T = 2 and a(1) = 2. MATHEMATICA f[n_] := If[EvenQ[n], PartitionsP[3n + 1], PartitionsP[(3n + 1)/2]]; Table[ f[n], {n, 35}] (* Robert G. Wilson v, Nov 07 2005 *) CROSSREFS Cf. A000546, A070165, A006577. Sequence in context: A104773 A128759 A066582 * A344889 A059445 A077518 Adjacent sequences: A111326 A111327 A111328 * A111330 A111331 A111332 KEYWORD nonn AUTHOR Parthasarathy Nambi, Nov 04 2005 STATUS approved

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Last modified March 23 23:09 EDT 2023. Contains 361454 sequences. (Running on oeis4.)