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.

A351704 Sums of the ascending diagonals of the triangle A162609.

Original entry on oeis.org

1, 1, 2, 3, 7, 10, 20, 26, 45, 55, 86, 101, 147, 168, 232, 260, 345, 381, 490, 535, 671, 726, 892, 958, 1157, 1235, 1470, 1561, 1835, 1940, 2256, 2376, 2737, 2873, 3282, 3435, 3895, 4066, 4580, 4770, 5341, 5551, 6182, 6413, 7107, 7360, 8120, 8396, 9225, 9525, 10426, 10751, 11727, 12078, 13132, 13510, 14645
Offset: 0

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Author

Eddie Gutierrez, May 05 2022

Keywords

Comments

Each term is the sum of an ascending diagonal of the triangle A162609.

Examples

			a(4) = (64 + 8 + 12)/12 = 7
a(5) = (250 - 75 + 50 + 15)/24 = 10.
		

Crossrefs

Cf. A162609.

Programs

  • C
    // Calculates and prints out the triangle and terms of ascending diagonals (on first line). To get more terms increment j.
    #include 
    int main()
    {
       int n, j=8, k, C, F1, F2,s;
       F1=1; F2=1;
       printf("%d ", F1);
       printf("%d ", F2);
       for (s=0;s<=j;s++)
       {
          F1=F1 + 2*s*s + 2*s + 1;
          F2=F2 + 2*s*s + 3*s + 2;
          printf("%d ", F1);
          printf("%d ", F2);
       }
       printf("\n");
       return 0;
    }

Formula

a(n) = (n^3 + 2*n + 12)/12, for even n.
a(n) = (2*n^3 - 3*n^2 + 10*n + 15)/24, for odd n.