STATUS
reviewed
approved
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Revision History for A317585
(Bold, blue-underlined text is an addition; faded, red-underlined text is aShowing entries 1-10 | older changes
a(n) = number of k with 1 <= k <= n-1 such that abs(a(k) - a(n-k)) <= 2.
(history; published version)
(history; published version)
STATUS
proposed
reviewed
STATUS
editing
proposed
LINKS
Rémy Sigrist, <a href="/A317585/b317585.txt">Table of n, a(n) for n = 1..10000</a>
STATUS
approved
editing
STATUS
proposed
approved
STATUS
editing
proposed
FORMULA
For n = 5:
- |a(1) - a(4)| = |0 - 3| = 3 > 2,
- |a(2) - a(3)| = |1 - 2| = 1 <= 2,
- |a(3) - a(2)| = |2 - 1| = 1 <= 2,
- |a(4) - a(1)| = |3 - 0| = 3 > 2,
- hence a(5) = 2.
LINKS
Rémy Sigrist, <a href="/A317585/a317585.png">Colored scatterplot of the first 100000 terms</a> (where the color is function of the parity of n)
PROG
(PARI) a = vector(75); for (n=1, #a, a[n] = sum(k=1, n-1, abs(a[k]-a[n-k])<=2); print1 (a[n] ", "))