A007162 -id:A007162 - cp's OEIS frontend

A007161 Number of blobs with vertical symmetry.

1, 1, 4, 15, 62, 262, 1148, 5123, 23316, 107570, 502664, 2372786, 11302858, 54256236, 262226900, 1274944859, 6231845040, 30605344282, 150948390672, 747356368322, 3713140528364, 18506907541124, 92509837573736, 463660345091686

Offset: 0

N. J. A. Sloane

nonn

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

R. C. Read, On the enumeration of a class of plane multigraphs, Aequat. Math. 31 (1986) no 1, 47-63.

Cf. A007162.

a(n) = coefficient of x^(2n+1) in x + D(x)^3/(1-D(x)^2) where D(x) = Sum_{k=0..infinity} A007162(k) * x^(2*k+1). - Sean A. Irvine, Nov 06 2017

a(9) corrected and more terms from Sean A. Irvine, Nov 06 2017

A007163 Number of P-graphs with vertical symmetry.

Original entry on oeis.org

1, 3, 10, 39, 158, 674, 2944, 13191, 60078, 277890, 1300536, 6151078, 29346036, 141088632, 682825140, 3324172359, 16267134462, 79975707362, 394833880540, 1956620531762, 9729300574580, 48529814786620, 242757311049680, 1217508537475894

Offset: 1

N. J. A. Sloane

nonn

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

R. C. Read, On the enumeration of a class of plane multigraphs, Aequat. Math. 31 (1986) no 1, 47-63.

Cf. A007162.

a(n) = coefficient of x^(2*n) in D(x)^2 / (1-D(x)^2) where D(x) = Sum_{k=0..infinity} A007162(k) * x^(2*k+1). - Sean A. Irvine, Nov 06 2017

a(9)-a(10) corrected and more terms from Sean A. Irvine, Nov 06 2017

cp's OEIS Frontend

A007161 Number of blobs with vertical symmetry.

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