1,1

Also nonisomorphic relations on 3-state logic.

F. Harary and R. W. Robinson, Exposition of the enumeration of point-line-signed graphs, pp. 19 - 33 of Proc. Second Caribbean Conference Combinatorics and Computing (Bridgetown, Jan. 4-7, 1977). Ed. R. C. Read and C. C. Cadogan. University of the West Indies, Cave Hill Campus, Barbados, 1977. vii+223 pp.

F. Harary, Palmer, Edgar M.; Robinson, Robert W.; Schwenk, Allen J.; Enumeration of graphs with signed points and lines. J. Graph Theory 1 (1977), no. 4, 295-308.

R. W. Robinson, personal communication.

R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1976.

R. W. Robinson, Table of n, a(n) for n = 1..13

a(n) = sum {1*s_1+2*s_2+...=n} (fix A[s_1, s_2, ...]/(1^s_1*s_1!*2^s_2*s_2!*...)) where fix A[s_1, s_2, ...] = 3^sum {i, j>=1} (gcd(i, j)*s_i*s_j).

Cf. A053467.

Cf. A000595, A053467.

Sequence in context: A012747 A027637 A099168 this_sequence A060336 A057863 A124488

Adjacent sequences: A004102 A004103 A004104 this_sequence A004106 A004107 A004108

easy,nonn

njas

More terms from Vladeta Jovovic (vladeta(AT)Eunet.yu), Jan 14 2000

Formula from Christian G. Bower (bowerc(AT)usa.net), Jan 06 2004