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.

Showing 1-2 of 2 results.

A037174 Primes which are not the sum of consecutive composite numbers.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 47, 61, 73, 107, 167, 179, 313, 347, 421, 479, 719, 863, 1153, 1213, 1283, 1307, 1523, 3467, 3733, 4007, 4621, 4787, 5087, 5113, 5413, 7523, 7703, 9817, 10333, 12347, 12539, 13381, 17027, 18553, 19717, 19813, 23399, 26003, 31873, 36097, 38833
Offset: 1

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Author

Keywords

Comments

It seems reasonable that a(n)/A079149(n) has an asymptote that could be estimated. - Peter Munn, Aug 21 2023

Crossrefs

Subsequence of A079149.
With {1}, the complement of A133576.
Primes that are the sum of specific numbers of consecutive composite numbers: A060254 (2), A060328 (3), A060329 (4), A060330 (5), A060331 (6), A060332 (7), A060333 (8).

Programs

  • Maple
    N:= 5000:
    primes,comps:= selectremove(isprime,{$2..N}):
    M:= nops(comps):
    X:= primes:
    for n from 1 to floor(sqrt(2*N)) do
    i:= 1;
    T:= add(comps[k],k=1..n);
    while T <= N do
    X := X minus {T};
    if i + n > M then break fi;
    T := T + comps[i+n] - comps[i];
    i := i+1;
    od;
    od:
    X;
    # Robert Israel, Jun 24 2008

Extensions

More terms from Jud McCranie, Jul 12 2000
Corrected by T. D. Noe, Aug 15 2008

A133575 Table, read by rows, giving the number of vertices possible in 2 X n nondegenerate classical transportation polytopes.

Original entry on oeis.org

3, 4, 5, 6, 4, 6, 8, 10, 12, 5, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
Offset: 3

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Author

Jonathan Vos Post, Sep 17 2007

Keywords

Comments

This paper discusses properties of the graphs of 2-way and 3-way transportation polytopes, in particular, their possible numbers of vertices and their diameters. Our main results include a quadratic bound on the diameter of axial 3-way transportation polytopes and a catalog of non-degenerate transportation polytopes of small sizes. The catalog disproves five conjectures about these polyhedra stated in the monograph by Yemelichev et al. (1984). It also allowed us to discover some new results. For example, we prove that the number of vertices of an m X n transportation polytope is a multiple of the greatest common divisor of m and n.

Examples

			Table 1 of De Loera et al.
size |dimension|Possible numbers of vertices
2.X.3|....2....|3.4..5..6
2.X.4|....3....|4.6..8.10.12
2.X.5|....4....|5.8.11.12.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30
		

Crossrefs

Showing 1-2 of 2 results.