login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A280689 as a simple table

na(n)
11
21
31
41
51
62
71
83
92
105
111
124
131
1413
155
167
171
1817
191
2011
2113
2289
231
2418
255
26233
2717
2829
291
30122
311
3247
3389
341597
3513
3676
371
384181
39233
40123
411
42842
431
44199
45122
4628657
471
48322
4913
5015005
511597
52521
531
545777
5589
56843
574181
58514229
591
601364
611
621346269
63842
642207
65233
6639602
671
683571
6928657
70709805
711
725778
731
7424157817
7515005
769349
7789
78271442
791
8015127
815777

[1,1,1,1,1,2,1,3,2,5,1,4,1,13,5,7,1,17,1,11,13,89,
 1,18,5,233,17,29,1,122,1,47,89,1597,13,76,1,4181,
 233,123,1,842,1,199,122,28657,1,322,13,15005,1597,
 521,1,5777,89,843,4181,514229,1,1364,1,1346269,
 842,2207,233,39602,1,3571,28657,709805,1,5778,1,
 24157817,15005,9349,89,271442,1,15127,5777]