OFFSET
1,1
COMMENTS
Let us denote P(n) = A000041(n) the partition numbers, and T(n,k) = A008284(n,k) the number of partitions of n with k parts.
All n = 2*P(k) > 4 (n = 6, 10, 14, 22, 30, 44, 60, 84, 112, 154, 202, ...) and also all n = 2*P(k) + 1 > 4 (n = 5, 7, 11, ...) are in this sequence: In this case, T(n,2) = P(k) = T(n,n-k), cf. formulas for A008284. For example, for n = 2*P(4) = 10, T(10, 2) = 5 = T(10, 6); for n = 2*P(3) + 1 = 7, T(7,2) = 3 = T(7,4).
Some terms (8, 13, 19, 26, 34, 43, 46, 68) are not of the form 2*P(k) or 2*P(k)+1. No such term is known beyond 68: Are there any others?
In some rare cases (11, 14, 60) there is more than one pair of repeated values. Are there other such cases beyond 60?
LINKS
M. F. Hasler, in reply to Hans Havermann, Re: Finite Sequence?, Sept. 26, 2017.
Jonathan Stauduhar, Is this sequence of numbers related to partitions finite?, Mathematics Stack Exchange, Sept. 17, 2017.
EXAMPLE
Denote by A8284(n) the n-th row of the table A008284. Then, for example:
A8284(8) = [1, 4, 5*, 5*, 3, 2, 1, 1]
A8284(11) = [1, 5*, 10**, 11, 10**, 7, 5*, 3, 2, 1, 1]
A8284(13) = [1, 6, 14*, 18**, 18**, 14*, 11, 7, 5, 3, 2, 1, 1]
A8284(14) = [1, 7*, 16, 23**, 23**, 20, 15, 11, 7*, 5, 3, 2, 1, 1]
A8284(19) = [1, 9, 30*, 54, 70, 71, 65, 52, 41, 30*, 22, 15, 11, 7, 5, 3, 2, 1, 1]
A8284(26) = [1, 13, 56*, 136, 221, 282, 300, 288, 252, 212, 169, 133, 101, 77, 56*, 42, 30, ...], where "..." represents the tail of the preceding list.
A8284(34) = [1, 17, 96, 297*, 603, 931, 1175, 1297, 1291, 1204, 1060, 905, 747, 608, 483, 383, 297*, 231, 176, 135, 101, ...]
A8284(43) = [1, 21, 154, 588, 1469, 2702, 4011, 5066, 5708*, 5888, 5708*, 5262, 4691, 4057, 3446, 2871, 2369, 1928, 1563, 1251, 1001, 792, 627, 490, 385, 297, ...]
A8284(46) = [1, 23, 176*, 720, 1898, 3692, 5731, 7564, 8824, 9418, 9373, 8877, 8073, 7139, 6158, 5231, 4370, 3621, 2965, 2417, 1951, 1573, 1255, 1002, 792, ...]
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
M. F. Hasler, Sep 26 2017
STATUS
approved