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A087077
Total number of elements in all primitive subsets of the integers 1 to n.
4
0, 1, 2, 5, 8, 21, 29, 73, 105, 193, 288, 677, 853, 1957, 2961, 4913, 6809, 15145, 19605, 43105, 57889, 98849, 151457, 327505, 397825, 784945, 1201189, 2009229, 2772729, 5901185, 7364945, 15609825, 21206049, 36440033, 55602033, 105010513, 127336513, 267374561
OFFSET
0,3
COMMENTS
A primitive set has no element that divides another element in the same set.
REFERENCES
R. K. Guy, Unsolved Problems in Number Theory, Springer-Verlag, New York, (1994).
LINKS
Fausto A. C. Cariboni, Table of n, a(n) for n = 0..75
Eric Weisstein's World of Mathematics, Primitive Sequence.
FORMULA
a(n) = Sum_{k=1..ceiling(n/2)} k * A355145(n,k). - Alois P. Heinz, Jun 27 2022
EXAMPLE
a(4)=8 since the primitive subsets of (1,2,3,4) are ( ) (1) (2) (3) (4) (2,3) (3,4) and these contain eight elements
CROSSREFS
A051026 gives the number of primitive subsets. A087078 gives the sum of the elements of the primitive subsets. A087080 gives the number elements in the coprime subsets.
Cf. A355145.
Sequence in context: A107384 A205596 A092446 * A200276 A168081 A340399
KEYWORD
nonn
AUTHOR
Alan Sutcliffe (alansut(AT)ntlworld.com), Aug 10 2003
EXTENSIONS
Terms a(34)-a(37) from Fausto A. C. Cariboni, Feb 02 2022
STATUS
approved