The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

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 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A094280 a(1)=1 (first row) and then the n-th row of this triangle contains the least set of n unused natural numbers whose sum is k * the sum of the previous row, with k being an integer > 1. 6
 1, 2, 3, 4, 5, 6, 7, 8, 9, 21, 10, 11, 12, 13, 44, 14, 15, 16, 17, 18, 100, 19, 20, 22, 23, 24, 25, 227, 26, 27, 28, 29, 30, 31, 32, 517, 33, 34, 35, 36, 37, 38, 39, 40, 1148, 41, 42, 43, 45, 46, 47, 48, 49, 50, 2469, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 5205, 61 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The first (n-1) terms of the n-th row contain n-1 smallest natural numbers which have not occurred earlier and the last term is chosen to satisfy the requirement. Permutation A076105 is defined similarly, but k is allowed to be 1. LINKS EXAMPLE Sixth row (14,15,16,17,18,100) has the sum 180 and by taking the next six least unused terms: (19,20,22,23,24,25), their sum is 133, for which 227 is the first unused term, so that sum 133+227 = 360 is a multiple of 180. CROSSREFS Inverse: A122156. Permutation A076105 is defined almost similarly. Cf. A094281, A094282, A094283, A094284. Sequence in context: A330927 A319387 A076105 * A082323 A069571 A039173 Adjacent sequences:  A094277 A094278 A094279 * A094281 A094282 A094283 KEYWORD nonn,tabl AUTHOR Amarnath Murthy, Apr 27 2004 EXTENSIONS Edited, extended and Scheme code added by Antti Karttunen, Aug 25 2006 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 8 10:17 EST 2021. Contains 349594 sequences. (Running on oeis4.)