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A125777 Moessner triangle based on A000217. 2
1, 3, 6, 13, 28, 21, 69, 161, 137, 55, 433, 1078, 1017, 477, 120, 3141, 8245, 8437, 4460, 1337, 231, 25873, 71008, 77620, 45058, 15415, 3220, 406, 238629, 680451, 786012, 492264, 186729, 44955, 6930, 666, 2436673, 7184170, 8699205, 5804448, 2394150 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Left border = A104989: (1, 3, 13, 69, 433...). Right border = the doubly triangular numbers starting (1, 6, 21...): A002817.

REFERENCES

J. H. Conway and R. K. Guy, "The Book of Numbers", Springer-Verlag, 1996, p. 64.

LINKS

Joshua Zucker, Table of n, a(n) for n = 1..55

FORMULA

Begin with the triangular numbers A000217 and circle every T(k)-th term, getting the doubly triangular numbers, A002817. Per instructions shown in A125714, take partial sums of the uncircled terms in row 1, denoting this as row 2. Circle the row 2 terms which are one place to the left of row 1 terms. Take partial sums again in analogous operations for subsequent rows.

EXAMPLE

First few rows of the triangle are:

1;

3, 6;

13, 28, 21;

69, 161, 137, 55;

433, 1078, 1017, 477, 120;

...

CROSSREFS

Cf. A125714, A002817, A104989, A000217.

Sequence in context: A036886 A052251 A032253 * A103788 A182137 A106461

Adjacent sequences:  A125774 A125775 A125776 * A125778 A125779 A125780

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Dec 07 2006

EXTENSIONS

More terms from Joshua Zucker, Jun 17 2007

STATUS

approved

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Last modified March 25 10:31 EDT 2019. Contains 321470 sequences. (Running on oeis4.)