

A094280


a(1)=1 (first row) and then the nth 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 (n1) terms of the nth row contain n1 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

Table of n, a(n) for n=1..67.
Index entries for sequences that are permutations of the natural numbers


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



