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A334745 Starting with a(1) = a(2) = 1, proceed in a square spiral, computing each term as the sum of diagonally adjacent prior terms. 2
1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 3, 2, 3, 1, 1, 3, 2, 3, 1, 1, 3, 3, 3, 3, 1, 1, 3, 3, 3, 3, 1, 1, 4, 3, 6, 3, 4, 1, 1, 4, 3, 6, 3, 4, 1, 1, 4, 4, 6, 6, 4, 4, 1, 1, 4, 4, 6, 6, 4, 4, 1, 1, 5, 4, 10, 6, 10, 4, 5, 1, 1, 5, 4, 10, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,8

COMMENTS

Conjecture: a(2n-1) = A247976(n).

LINKS

Peter Kagey, Table of n, a(n) for n = 1..10000

Peter Kagey, Bitmap illustrating the of parity of the first 2^22 terms. (Even and odd numbers are represented with black and white pixels respectively.)

EXAMPLE

Spiral begins:

... 3---3---3---3---1

                    |

1---1---2---2---1   1

|               |   |

2   1---1---1   1   3

|   |       |   |   |

2   1   1---1   2   2

|   |           |   |

1   1---2---1---1   3

|                   |

1---3---2---3---1---1

The last illustrated term above is a(35) = 3 = 2 + 1 because diagonally down-right is 2 and diagonally down-left is 1.

CROSSREFS

Cf. A141481, A278180, A334741, A334742.

The x- and y-coordinates at n-th step are A174344 and A274923 respectively.

Sequence in context: A307017 A220424 A182907 * A323231 A175128 A205154

Adjacent sequences:  A334742 A334743 A334744 * A334746 A334747 A334748

KEYWORD

nonn

AUTHOR

Alec Jones and Peter Kagey, May 09 2020

STATUS

approved

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Last modified June 26 12:42 EDT 2022. Contains 354883 sequences. (Running on oeis4.)