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A340028
Number of unlabeled 2-connected graphs with n vertices rooted at a pair of noninterchangeable vertices.
2
0, 1, 1, 7, 55, 655, 11147, 287791, 11787747, 804475261, 94875366649, 19825870580671, 7466490852631207, 5129453728126116131, 6487332587944013948099, 15213161506747424007012971, 66536415576917924594383104139, 545371527333985035460963541248785
OFFSET
1,4
LINKS
PROG
(PARI) \\ See A004115 for graphsSeries and A339645 for combinatorial species functions.
cycleIndexSeries(n)={my(g=graphsSeries(n), gcr=sPoint(g)/g); x*sPoint(sSolve( sLog( gcr/(x*sv(1)) ), gcr ))}
{ my(N=15); Vec(OgfSeries(cycleIndexSeries(N)), -N) }
CROSSREFS
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Jan 02 2021
STATUS
approved