OFFSET
0,3
COMMENTS
See A092481 for the definition of isotemporal classes.
REFERENCES
Benjamin de Bivort, Isotemporal classes of diasters, beachballs and daisies, preprint, 2005.
FORMULA
a(n=2k) = 1 + sum_{i=1}^{(n/2)-1} (n*i-i^2+n+1) + (1/2)((n/2)^2+3(n/2)+2) a(n=2k+1)= 1 + sum_{i=1}^{(n-1)/2} ((n*i-i^2+n+1). [Corrected by Sean A. Irvine after private communication with Benjamin de Bivort, Feb 13 2012]
a(n) = A005993(n) - n. - Enrique Pérez Herrero, Apr 22 2012
EXAMPLE
A diaster is defined to be any graph with a central edge with vertices of degree j and k and j+k peripheral edges connected to the central edge each terminating in a vertex of degree 1. a(5)=23 refers to diasters with 5 peripheral edges. These can be uniquely arranged with 0, 1 or 2 peripheral edges on a particular side, yielding 1, 10 and 12 isotemporal classes respectively each.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Benjamin de Bivort (bivort(AT)fas.harvard.edu), Aug 02 2005
EXTENSIONS
More terms from Sean A. Irvine, Feb 12 2012
STATUS
approved