cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A182043 Table, by rows, of T(k,n) the number of simple graphs on v = prime(n) vertices and with e = prime(k) edges.

Original entry on oeis.org

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

Views

Author

Jonathan Vos Post, Apr 07 2012

Keywords

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 |
  +---+---+---+---+---+
		

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