

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
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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", SpringerVerlag, 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



