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.

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A380502 a(n) = (7*n^6 - 21*n^5 + 55*n^4 - 75*n^3 + 70*n^2 - 36*n + 8)/8.

Original entry on oeis.org

1, 1, 34, 370, 2179, 8791, 27586, 72514, 167245, 348949, 672706, 1216546, 2087119, 3425995, 5416594, 8291746, 12341881, 17923849, 25470370, 35500114, 48628411, 65578591, 87193954, 114450370, 148469509, 190532701, 242095426, 304802434, 380503495, 471269779, 579410866
Offset: 0

Views

Author

Kelvin Voskuijl, Jan 25 2025

Keywords

Comments

From a(1) onwards, first differences of A075664 (sum of next n cubes).

Crossrefs

Cf. A075664.
Cf. A005448 (first differences of sum of next n natural numbers), A380353 (for sum of next n squares).

Programs

  • Mathematica
    Table[(7 * n^6 - 21 * n^5 + 55 * n^4 - 75 * n^3 + 70 * n^2 - 36 * n + 8) / 8, {n, 1, 30}]
  • PARI
    a(n) = (7*n^6 - 21*n^5 + 55*n^4 - 75*n^3 + 70*n^2 - 36*n + 8)/8
    
  • Python
    def A380502(n): return (n*(n*(n*(n*(n*(7*(n-3))+55)-75)+70)-36)>>3)+1 # Chai Wah Wu, Feb 09 2025

Formula

G.f.: (1 - 6*x + 48*x^2 + 118*x^3 + 303*x^4 + 132*x^5 + 34*x^6)/(1 - x)^7. - Stefano Spezia, Jan 28 2025
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