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.

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

Offset

1,1

Comments

In contrast to A225376-A225378, 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 A225376-A225378, 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: A329598 A248469 A331952 * A037258 A201993 A024521

Adjacent sequences: A225383 A225384 A225385 * A225387 A225388 A225389

Keyword

nonn

Author

N. J. A. Sloane, May 15 2013

Status

approved