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.

A384127 a(n) is the number of integer quintuples (a,b,c,d,e) satisfying a system of linear inequalities and congruences specified in the comments.

Original entry on oeis.org

1, 25, 226, 1000, 3126, 7877, 17151, 33602, 60751, 103127, 166378, 257402, 384478, 557377, 787503, 1088004, 1473903, 1962229, 2572128, 3325004, 4244630, 5357279, 6691855, 8280004, 10156255, 12358131, 14926280, 17904606, 21340380, 25284381, 29791007, 34918406
Offset: 0

Views

Author

Jeffery Opoku, May 19 2025

Keywords

Comments

The inequalities are
n + a + b + c + d + e >= 0,
121*n + 61*a + 13*b - 23*c - 47*d - 59*e >= 0,
121*n + 13*a - 47*b - 59*c - 23*d + 61*e >= 0,
121*n - 23*a - 59*b + 13*c + 61*d - 47*e >= 0,
121*n - 47*a - 23*b + 61*c - 59*d + 13*e >= 0,
121*n - 59*a + 61*b - 47*c + 13*d - 23*e >= 0,
The congruences are
n + a + b + c + d + e == 0 (mod 12),
121*n + 61*a + 13*b - 23*c - 47*d - 59*e == 0 (mod 11).

Examples

			For n=0, the sole solution is (a,b,c,d,e) = (0,0,0,0,0) so a(0) = 1.
For n=1, the a(1)=25 solutions are (-3,3,-1,0,0), (-2,0,2,-1,0), (-2,1,-1,2,-1), (-1,-2,2,1,-1), (-2,1,0,-1,1), (-1,-1,0,1,0), (0,-3,0,3,-1), (-1,-1,1,-2,2), (-1,0,-2,1,1), (0,-2,-1,0,2), (0,-1,-3,0,3), (-1,0,3,-3,0), (-1,1,0,0,-1), (0,-1,0,2,-2), (-1,2,-2,0,0), (0,-1,1,-1,0), (0,0,-1,-1,1), (1,-2,-1,1,0), (0,1,1,-2,-1), (1,-1,1,0,-2), (1,0,-1,0,-1), (2,-1,-2,-1,1), (1,2,-1,-1,-2), (2,0,0,-2,-1), (3,0,0,-1,-3).
		

Crossrefs

Programs

  • Mathematica
    a[n_] :=
      Sum[Sum[Sum[
         Sum[Sum[Boole[
            PossibleZeroQ[
             Mod[-b + 3 n + 4 q1 + 3 q2 + q3 + 2 q4, 5]]], {q4, 0,
            Floor[5 n - 5 b - q1 - q2 - q3]}], {q3, 0,
           Floor[5 n - 5 b - q1 - q2]}], {q2, 0,
          Floor[5 n - 5 b - q1]}], {q1, 0, Floor[5 n - 5 b]}], {b, 0,
        Floor[n]}];
    Table[a[j], {j, 0, 50}]

Extensions

More terms from Jinyuan Wang, May 26 2025

A384295 a(n) is the number of integer sextuples (a,b,c,d,e,f) satisfying a system of linear inequalities and congruences specified in the comments.

Original entry on oeis.org

1, 42, 684, 4388, 17976, 56076, 145630, 331410, 682596, 1300338, 2326422, 3952896, 6432777, 10091748, 15340947, 22690710, 32765418, 46319334, 64253491, 87633588, 117708960, 155932526, 203981823, 263781030, 337524061, 427698636, 537111456, 668914338, 826631436
Offset: 0

Views

Author

Jeffery Opoku, May 24 2025

Keywords

Comments

The inequalities are
n + a + b + c + d + e + f >= 0,
169*n + 97*a + 37*b - 11*c - 47*d - 71*e - 83*f >= 0,
169*n + 37*a - 47*b - 83*c - 71*d - 11*e + 97*f >= 0,
169*n - 11*a - 83*b - 47*c + 97*d + 37*e - 71*f >= 0,
169*n - 47*a - 71*b + 97*c - 11*d - 83*e + 37*f >= 0,
169*n - 71*a - 11*b + 37*c - 83*d + 97*e - 47*f >= 0,
169*n - 83*a + 97*b - 71*c + 37*d - 47*e - 11*f >= 0.
The congruences are
n + a + b + c + d + e + f == 0 (mod 12),
169*n + 97*a + 37*b - 11*c - 47*d - 71*e - 83*f == 0 (mod 13).

Examples

			For n=0, the sole solution is (a,b,c,d,e,f) = (0,0,0,0,0,0) so a(0) = 1.
For n=1, the a(1)=42 solutions are (-3, 3, -1, 0, 0, 0), (-2, 0, 2, -1, 0, 0), (-2, 1, -1, 2, -1, 0), (-2, 1, 0, -1, 2, -1), (-2, 1, 0, 0, -1, 1), (-1, -2, 2, 1, -1, 0), (-1, -1, 0, 1, 1, -1), (-1, -1, 1, -1, 1, 0), (-1, -1, 1, 0, -2, 2), (-1, 0, -2, 2, 0, 0), (-1, 0, -1, 0, 0, 1), (-1, 0, 0, -3, 3, 0), (-1, 0, 1, 1, -2, 0), (-1, 0, 2, -2, 1, -1), (-1, 1, -1, 1, 0, -1), (-1, 1, 0, -1, 0, 0), (-1, 2, -2, 0, -1, 1), (0, -3, 0, 3, 0, -1), (0, -2, -1, 1, 2, -1), (0, -2, 0, 0, -1, 2), (0, -1, -2, 0, 1, 1), (0, -1, -1, -2, 1, 2), (0, -1, 0, 0, 2, -2), (0, -1, 0, 1, -1, 0), (0, -1, 1, -1, -1, 1), (0, -1, 3, 0, -3, 0), (0, 0, -3, -1, 0, 3), (0, 0, -1, -1, 1, 0), (0, 0, 1, 0, -1, -1), (0, 1, 0, -2, 1, -1), (0, 2, 0, 0, -2, -1), (1, -2, -1, 1, 0, 0), (1, -1, -1, 2, 0, -2), (1, -1, 0, 0, 0, -1), (1, 0, -1, -1, -1, 1), (1, 0, 1, -1, 0, -2), (1, 1, -1, 0, -1, -1), (1, 2, 0, -1, -1, -2), (2, -1, -2, -1, 0, 1), (2, 0, -1, -2, 0, 0), (2, 0, 1, -1, -2, -1), (3, 0, 0, 0, -1, -3).
		

Crossrefs

Programs

  • Mathematica
    a[n_]:=Sum[Boole[Mod[12*n+25*b-11*t1+9*t2-7*t3+2*t4-6*t5,19]==0],{b,0,Floor[7*n/6]},{t1,0,Floor[7*n-6*b]},{t2,0,Floor[7*n-6*b-t1]},{t3,0,Floor[7*n-6*b-t1-t2]},{t4,0,Floor[7*n-6*b-t1-t2-t3]},{t5,0,Floor[7*n-6*b-t1-t2-t3-t4]}];
    Table[a[j],{j,0,20}]

Extensions

More terms from Jinyuan Wang, May 26 2025
a(29) and a(30) from Ray Chandler, Jun 04 2025
Showing 1-2 of 2 results.