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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A170804 Partial sums of (A006899, prefixed by a 1).

Original entry on oeis.org

1, 2, 4, 7, 11, 19, 28, 44, 71, 103, 167, 248, 376, 619, 875, 1387, 2116, 3140, 5188, 7375, 11471, 18032, 26224, 42608, 62291, 95059, 154108, 219644, 350716, 527863, 790007, 1314295, 1845736, 2894312, 4488635, 6585787, 10780091, 15563060, 23951668, 38300575
Offset: 1

Views

Author

N. J. A. Sloane, Dec 12 2009

Keywords

Comments

a(n) is the minimum number of three-in-a-rows passing through any cell in n-dimensional tic-tac-toe = the minimum value in the n-th row of A352419. - Ben Orlin, Mar 22 2022

Crossrefs

Cf. A006899.
Equals A170803 + 1.
Minimum value in the n-th row of A352419.

Programs

  • Python
    from sympy import integer_log
def A170804(n): return 1 if n == 1 else ((a:=1<>1) if 6**(k:=integer_log(m:=3**(n-2),6)[0])<<1>1)+(1<Chai Wah Wu, Feb 05 2025
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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