A369385 The smallest number k that can be partitioned in n ways as the sum of two numbers from A109611.
1, 4, 10, 22, 34, 60, 118, 112, 142, 198, 270, 298, 280, 364, 508, 460, 588, 490, 580, 658, 858, 670, 700, 994, 880, 1240, 1078, 1288, 910, 1120, 1428, 1510, 1300, 1330, 1930, 1960, 1750, 1540, 2128, 2170, 2140, 2470, 2560, 2380, 2590, 2770, 2728, 3838, 2968, 4000
Offset: 0
Keywords
Examples
a(0) = 1 because 1 cannot be written as the sum of two terms in A109611. The numbers 2 and 3 cannot be written as the sum of two terms in A109611, and 4 = 2 + 2 = A109611(1) + A109611(1) is the only writing with terms in A109611, so a(1) = 4. The numbers 5, 6, 7, 8, 9 can be written as the sum of two terms in A109611 in at most one way and 10 = 3 + 7 = A109611(2) + A109611(4) and 10 = 5 + 5 = A109611(3) + A109611(3), so a(2) = 10.
Crossrefs
Cf. A109611.
Programs
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Magma
IsSemiprime:=func
; ch:=func ; b:=[n: n in [1..4000] |ch(n)]; a:=[]; for n in [0..47] do k:=1; while #RestrictedPartitions(k, 2, Set(b)) ne n do k:=k+1; end while; Append(~a,k); end for; a;