

A225386


Construct sequences P,Q,R by the rules: Q = first differences of P, R = second differences of P, P starts with 1,3,9, Q starts with 2,6, R starts with 4; at each stage the smallest number not yet present in P,Q,R is appended to R. Sequence gives Q.


4



2, 6, 11, 18, 26, 36, 48, 61, 75, 90, 106, 123, 142, 163, 185, 208, 232, 257, 284, 312, 341, 371, 402, 434, 467, 501, 536, 573, 612, 652, 693, 735, 778, 822, 867, 913, 960, 1009, 1059, 1110, 1162, 1215, 1269, 1324, 1380, 1437, 1495, 1554, 1614, 1676, 1739, 1804, 1870, 1937, 2005, 2074, 2144
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OFFSET

1,1


COMMENTS

In contrast to A225376A225378, here it is not required (and not true) that each number should appear just once in P union Q union R. On the other hand, again in contrast to A225376A225378, here it is obvious that P, Q, R are infinite.
The first three numbers that are repeated are 284, 2074, 3500, which appear in both P and Q. There may be no others. Of course R is disjoint from P and Q, by definition.


LINKS

Table of n, a(n) for n=1..57.


MAPLE

See A225385.


CROSSREFS

Cf. A225385, A225387, A005228, A030124, A037257, A225376, A225377, A225378.
Sequence in context: A239698 A039745 A248469 * A037258 A201993 A024521
Adjacent sequences: A225383 A225384 A225385 * A225387 A225388 A225389


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, May 15 2013


STATUS

approved



