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A244971 Number of regions in the symmetric representation of sigma(n) on the four quadrants. 7
1, 1, 4, 1, 4, 1, 4, 1, 8, 4, 4, 1, 4, 4, 8, 1, 4, 1, 4, 1, 12, 4, 4, 1, 8, 4, 12, 1, 4, 1, 4, 1, 12, 4, 8, 1, 4, 4, 12, 1, 4, 1, 4, 4, 8, 4, 4, 1, 8, 8, 12, 4, 4, 1, 12, 1, 12, 4, 4, 1, 4, 4, 16, 1, 12, 1, 4, 4, 12, 8, 4, 1, 4, 4, 12, 4, 8, 4, 4, 1, 16, 4, 4, 1, 12, 4, 12, 1, 4, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Partial sums give A244970.

Number of terraces at the n-th level (starting from the top) of the step pyramid described in A244050. - Omar E. Pol, Apr 20 2016

LINKS

Table of n, a(n) for n=1..90.

FORMULA

a(n) = 1, if A237271(n) = 1.

a(n) = 4*(A237271(n) - 1), if A237271(n) > 1.

EXAMPLE

From Omar E. Pol, Apr 20 2016: (Start)

Illustration of the top view of the step pyramid with 16 levels:

.                 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

.                |  _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _  |

.                | |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _| |

.             _ _| |  _ _ _ _ _ _ _ _ _ _ _ _ _ _  | |_ _

.           _|  _ _| |_ _ _ _ _ _ _ _ _ _ _ _ _ _| |_ _  |_

.         _|  _|  _| |  _ _ _ _ _ _ _ _ _ _ _ _  | |_  |_  |_

.        |  _|   |_ _| |_ _ _ _ _ _ _ _ _ _ _ _| |_ _|   |_  |

.   _ _ _| |  _ _|     |  _ _ _ _ _ _ _ _ _ _  |     |_ _  | |_ _ _

.  |  _ _ _|_| |      _| |_ _ _ _ _ _ _ _ _ _| |_      | |_|_ _ _  |

.  | | |  _ _ _|    _|_ _|  _ _ _ _ _ _ _ _  |_ _|_    |_ _ _  | | |

.  | | | | |  _ _ _| |  _| |_ _ _ _ _ _ _ _| |_  | |_ _ _  | | | | |

.  | | | | | | |  _ _|_|  _|  _ _ _ _ _ _  |_  |_|_ _  | | | | | | |

.  | | | | | | | | |  _ _|   |_ _ _ _ _ _|   |_ _  | | | | | | | | |

.  | | | | | | | | | | |  _ _|  _ _ _ _  |_ _  | | | | | | | | | | |

.  | | | | | | | | | | | | |  _|_ _ _ _|_  | | | | | | | | | | | | |

.  | | | | | | | | | | | | | | |  _ _  | | | | | | | | | | | | | | |

.  | | | | | | | | | | | | | | | |   | | | | | | | | | | | | | | | |

.  | | | | | | | | | | | | | | | |_ _| | | | | | | | | | | | | | | |

.  | | | | | | | | | | | | | |_|_ _ _ _|_| | | | | | | | | | | | | |

.  | | | | | | | | | | | |_|_  |_ _ _ _|  _|_| | | | | | | | | | | |

.  | | | | | | | | | |_|_    |_ _ _ _ _ _|    _|_| | | | | | | | | |

.  | | | | | | | |_|_ _  |_  |_ _ _ _ _ _|  _|  _ _|_| | | | | | | |

.  | | | | | |_|_ _  | |_  |_ _ _ _ _ _ _ _|  _| |  _ _|_| | | | | |

.  | | | |_|_ _    |_|_ _| |_ _ _ _ _ _ _ _| |_ _|_|    _ _|_| | | |

.  | |_|_ _ _  |     |_  |_ _ _ _ _ _ _ _ _ _|  _|     |  _ _ _|_| |

.  |_ _ _  | |_|_      | |_ _ _ _ _ _ _ _ _ _| |      _|_| |  _ _ _|

.        | |_    |_ _  |_ _ _ _ _ _ _ _ _ _ _ _|  _ _|    _| |

.        |_  |_  |_  | |_ _ _ _ _ _ _ _ _ _ _ _| |  _|  _|  _|

.          |_  |_ _| |_ _ _ _ _ _ _ _ _ _ _ _ _ _| |_ _|  _|

.            |_ _  | |_ _ _ _ _ _ _ _ _ _ _ _ _ _| |  _ _|

.                | |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _| |

.                | |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _| |

.                |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|

.

Note that the above diagram contains a hidden pattern, simpler, which emerges from the front view of every corner of the step pyramid.

For more information about the hidden pattern see A237593.

(End)

PROG

(PARI) lista() = {v = readvec("b237271.txt"); for (i=1, #v, vi = v[i]; if (vi == 1, w = 1, w = 4*(vi-1)); print1(w, ", "); ); } \\ Michel Marcus, Sep 29 2014

CROSSREFS

Cf. A000203, A196020, A235791, A236104, A237270, A237271, A237591, A237593, A239050, A239660, A239931-A239934, A244050, A244370, A244371, A244970, A245092.

Sequence in context: A010685 A174571 A099301 * A050347 A240226 A322515

Adjacent sequences:  A244968 A244969 A244970 * A244972 A244973 A244974

KEYWORD

nonn

AUTHOR

Omar E. Pol, Jul 08 2014

STATUS

approved

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Last modified April 5 06:13 EDT 2020. Contains 333238 sequences. (Running on oeis4.)