login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A256255 Triangle read by rows: T(n,k) = 6*k + 1, n>=0, 0<=k<=(2^n-1). 0
1, 1, 7, 1, 7, 13, 19, 1, 7, 13, 19, 25, 31, 37, 43, 1, 7, 13, 19, 25, 31, 37, 43, 49, 55, 61, 67, 73, 79, 85, 91, 1, 7, 13, 19, 25, 31, 37, 43, 49, 55, 61, 67, 73, 79, 85, 91, 97, 103, 109, 115, 121, 127, 133, 139, 145, 151, 157, 163, 169, 175, 181, 187, 1, 7, 13, 19, 25, 31, 37, 43, 49, 55, 61, 67, 73, 79, 85, 91, 97, 103 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Row n lists the first 2^n terms of A016921, n >= 0.

Row sums give A165665.

Right border gives A048488.

The sum of all terms of the first k rows gives A060867(k).

The product of the terms of the third row is equal to the Hardy-Ramanujan number: 1 * 7 * 13 * 19 = 1729.

LINKS

Table of n, a(n) for n=0..80.

EXAMPLE

Triangle begins:

1;

1,7;

1,7,13,19;

1,7,13,19,25,31,37,43;

1,7,13,19,25,31,37,43,49,55,61,67,73,79,85,91;

...

Illustration of initial terms in the fourth quadrant of the square grid:

------------------------------------------------------------------------

n   a(n)             Compact diagram

------------------------------------------------------------------------

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

0    1      |_|_  |_ _ _  |_ _ _ _ _ _ _  |

1    1      | |_| |_ _  | |_ _ _ _ _ _  | |

2    7      |_ _ _|_  | | |_ _ _ _ _  | | |

3    1      | | | |_| | | |_ _ _ _  | | | |

4    7      | | |_ _ _| | |_ _ _  | | | | |

5   13      | |_ _ _ _ _| |_ _  | | | | | |

6   19      |_ _ _ _ _ _ _|_  | | | | | | |

7    1      | | | | | | | |_| | | | | | | |

8    7      | | | | | | |_ _ _| | | | | | |

9   13      | | | | | |_ _ _ _ _| | | | | |

10  19      | | | | |_ _ _ _ _ _ _| | | | |

11  25      | | | |_ _ _ _ _ _ _ _ _| | | |

12  31      | | |_ _ _ _ _ _ _ _ _ _ _| | |

13  37      | |_ _ _ _ _ _ _ _ _ _ _ _ _| |

14  43      |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _|

.

a(n) is also the number of cells in the n-th region of the diagram.

For other diagrams of the same family see A241717 and A256258.

CROSSREFS

Cf. A000225, A001235, A016921, A048488, A060867, A165665, A241717, A256258.

Sequence in context: A151785 A093564 A081776 * A131115 A151778 A138616

Adjacent sequences:  A256252 A256253 A256254 * A256256 A256257 A256258

KEYWORD

nonn,tabf

AUTHOR

Omar E. Pol, Apr 30 2015

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 16 15:48 EDT 2019. Contains 328101 sequences. (Running on oeis4.)