A182043 Table, by rows, of T(k,n) the number of simple graphs on v = prime(n) vertices and with e = prime(k) edges.
1, 1, 2, 4, 6, 4, 2, 5, 21, 65, 148, 97, 10, 2, 2, 5, 26, 172, 10250, 75415, 2295898, 8640134, 53037356, 99187806, 70065437, 4609179, 192788, 28259, 467, 2, 2, 5, 26, 176, 14140, 154658, 17422984, 152339952, 6461056816, 359954668522, 899632282299, 4093273437761, 4093273437761
Offset: 2
Examples
T(3,4) = 4 because there are 4 simple graphs with prime(3) = 5 vertices and prime(4) = 7 edges. The table begins: +---+---+---+---+ |e=2|e=3|e=5|e=7| +---+---+---+---+---+ |v=3| 1 | 1 | | | +---+---+---+---+---+ |v=5| 2 | 4 | 6 | 4 | +---+---+---+---+---+
Links
- Eric Weisstein's World of Mathematics, Simple Graph.
Crossrefs
Cf. A008406.
Programs
-
Maple
read("transforms3") : L := BFILETOLIST("b008406.txt") ; A008406 := proc(n,k) global L ; local f,r ; f := 1 ; r := 1 ; while r < n do f := f+r*(r-1)/2+1 ; r := r+1 ; end do: op(f+k,L) ; end proc: for n from 1 do v := ithprime(n) ; for k from 1 do e := ithprime(k) ; if e > v*(v-1)/2 then break; else printf("%d,",A008406(v,e)) ; end if; end do: end do: # R. J. Mathar, Oct 20 2013
Extensions
Terms from row 4 on by R. J. Mathar, Oct 20 2013