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A233270

a(n) = A233271(n) - A179016(n).

0, 0, -1, 0, 0, 0, 1, 0, 0, 2, 1, 2, 0, 0, 3, 3, 4, 3, 4, 3, 3, 0, 0, 4, 4, 5, 4, 6, 5, 5, 3, 5, 5, 6, 4, 5, 4, 4, 0, 0, 5, 8, 9, 10, 13, 13, 15, 16, 17, 18, 18, 17, 17, 19, 19, 17, 17, 18, 18, 17, 16, 15, 13, 13, 10, 9, 8, 5, 0, 0, 6, 9, 14, 17, 18, 20, 22, 21

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OFFSET

0,10

COMMENTS

For all n>=2, a(1+A213710(n)) = n-2.

Except for a(2)=-1 (which seems to be the only negative term in the sequence), the sequences A218600 and A213710 give the positions of zeros.

Furthermore, each subrange [A213710(n)..A218600(n+1)] is palindromic. A233268 gives the middle points of those ranges, the sequence A234018 gives the values at those points, while A234019 gives the maximum term in that range in this sequence.

LINKS

Antti Karttunen, Rows 0..16, flattened

FORMULA

a(n) = A233271(n) - A179016(n).

a(A218602(n)) = a(n). [This is just a claim that each row is palindrome]

EXAMPLE

This irregular table begins as:

-1;

0, 0;

0, 1, 0;

0, 2, 1, 2, 0;

0, 3, 3, 4, 3, 4, 3, 3, 0;