A101708 Number of partitions of n having positive even rank (the rank of a partition is the largest part minus the number of parts).
0, 0, 0, 1, 0, 2, 1, 4, 3, 7, 6, 14, 13, 23, 24, 41, 43, 67, 75, 111, 126, 177, 204, 282, 328, 437, 514, 674, 793, 1021, 1207, 1533, 1814, 2273, 2691, 3344, 3956, 4865, 5754, 7027, 8296, 10060, 11864, 14302, 16836, 20183, 23715, 28301, 33191, 39423, 46152, 54607, 63794, 75200, 87687, 103018
Offset: 0
Keywords
Examples
a(7)=4 because the only partitions of 7 with positive even rank are 7 (rank=6), 61 (rank=4), 511 (rank=2) and 43 (rank=2).
References
- George E. Andrews, The Theory of Partitions, Addison-Wesley, Reading, Mass., 1976.
Programs
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Mathematica
Table[Count[Max[#]-Length[#]&/@IntegerPartitions[n],?(EvenQ[#] && Positive[#]&)], {n,50}] (* _Harvey P. Dale, Feb 26 2012 *)
Formula
G.f.: Sum((-1)^(k+1)*x^((3*k^2+3*k)/2)/(1+x^k), k>=1)/Product(1-x^k, k>=1). - Vladeta Jovovic, Dec 20 2004
Extensions
More terms from Joerg Arndt, Oct 07 2012
Offset changed to 0 by Georg Fischer, Dec 23 2023