Thursday, May 9, 2024

A370831 Contribution to the OEIS

 

A370831Alternating sum of composites.0
4, 2, 6, 3, 7, 5, 9, 6, 10, 8, 12, 9, 13, 11, 14, 12, 15, 13, 17, 15, 18, 16, 19, 17, 21, 18, 22, 20, 24, 21, 25, 23, 26, 24, 27, 25, 29, 26, 30, 27, 31, 29, 33, 30, 34, 31, 35, 33, 36, 34, 38, 36, 39, 37, 40, 38, 42, 39, 43, 41, 44, 42, 45, 43, 47, 44, 48, 45, 49, 46 (listgraphrefslistenhistoryedittextinternal format)
OFFSET
1,1
COMMENTS
Unlike equivalent sequence for primes, A008347, there are repeated terms.
LINKS
FORMULA
a(n) = A002808(n) - a(n-1), for n>1.
EXAMPLE
a(4) = 9 - 8 + 6 - 4 = 3.
MATHEMATICA
Join[{4}, a[1]=4; a[n_]:=ResourceFunction["Composite"][n] - a[n-1]; Table[a[n], {n, 2, 70}]] (* or with signs *) R=70; a[1]=4; a[n_]:=a[n-1]-ResourceFunction["Composite"][n] *(-1)^n; Table[a[n], {n, 70}]
CROSSREFS
Sequence in context: A246879 A302794 A247361 * A297307 A163238 A097362
KEYWORD
nonn
AUTHOR
James C. McMahon, Mar 02 2024
STATUS
approved

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