A379315 Number of strict integer partitions of n with a unique 1 or prime part.
0, 1, 1, 1, 0, 2, 1, 3, 1, 3, 2, 7, 3, 7, 4, 10, 7, 15, 7, 17, 13, 23, 16, 31, 20, 37, 31, 48, 38, 62, 48, 76, 68, 93, 80, 119, 105, 147, 137, 175, 166, 226, 208, 267, 263, 326, 322, 407, 391, 481, 492, 586, 591, 714, 714, 849, 884, 1020, 1050, 1232, 1263
Offset: 0
Keywords
Examples
The a(10) = 2 through a(15) = 10 partitions: (8,2) (11) (9,3) (13) (9,5) (8,7) (9,1) (6,5) (10,2) (7,6) (12,2) (10,5) (7,4) (6,4,2) (8,5) (8,4,2) (11,4) (8,3) (10,3) (9,4,1) (12,3) (9,2) (12,1) (14,1) (10,1) (6,4,3) (6,5,4) (6,4,1) (8,4,1) (8,4,3) (8,6,1) (9,4,2) (10,4,1)
Links
- Andrew Howroyd, Table of n, a(n) for n = 0..1000
Programs
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Mathematica
Table[Length[Select[IntegerPartitions[n],UnsameQ@@#&&Count[#,_?(#==1||PrimeQ[#]&)]==1&]],{n,0,30}]
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PARI
seq(n)={Vec(sum(k=1, n, if(isprime(k) || k==1, x^k)) * prod(k=4, n, 1 + if(!isprime(k), x^k), 1 + O(x^n)), -n-1)} \\ Andrew Howroyd, Dec 28 2024
Comments