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 A358243 Number of n-regular, N_0-weighted pseudographs on 2 vertices with total edge weight 3, up to isomorphism. 6
 1, 4, 9, 15, 21, 28, 34, 41, 47, 54, 60, 67, 73, 80, 86, 93, 99, 106, 112, 119, 125, 132, 138, 145, 151, 158, 164, 171, 177, 184, 190, 197, 203, 210, 216, 223, 229, 236, 242, 249, 255, 262, 268, 275, 281, 288, 294, 301, 307, 314, 320, 327, 333, 340, 346, 353 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Pseudographs are finite graphs with undirected edges without identity, where parallel edges between the same vertices and loops are allowed. LINKS Table of n, a(n) for n=1..56. FORMULA Apparently a(n) = A258589(n-2) + 2 for n>= 4, i.e., terms satisfy linear recurrence a(n) = a(n-1) + a(n-2) - a(n-3) for n>=7. - Hugo Pfoertner, Dec 02 2022 CROSSREFS Other total edge weights 4 (A358244), 5 (A358245), 6 (A358246), 7 (A358247), 8 (A358248), 9 (A358249). Cf. A258589. Sequence in context: A313297 A270545 A359626 * A099055 A162801 A335250 Adjacent sequences: A358239 A358240 A358241 * A358244 A358245 A358246 KEYWORD nonn AUTHOR Lars Göttgens, Nov 04 2022 STATUS approved

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Last modified December 7 12:41 EST 2023. Contains 367656 sequences. (Running on oeis4.)