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 A213626 a(n) = Sum_{0<=i
 0, 0, 1, -2, -2, 0, -5, -4, 0, 8, 21, 2, -10, -16, -15, -20, -20, -16, -7, -22, -14, 0, -21, -8, -28, -40, -45, -46, -42, -32, -49, -40, -24, 0, 33, -10, 22, 64, 11, 52, 104, 168, 245, 154, 78, 16, 65, 4, -44, -80, -105, -90, -114, -128, -123, -136, -132, -120 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..15000 MAPLE b:= proc(n) option remember; local r;       `if`(n=0, 1, `if`(irem(n, 2, 'r')=0, b(r), b(r)*(-1)^r))     end: s:= proc(j) option remember; `if`(j<0, 0, s(j-1)+b(j)       ) end: t:= proc(k) option remember; `if`(k<1, 0, t(k-1)+b(k)*s(k-1)) end: a:= proc(n) option remember; `if`(n<2, 0, a(n-1)+b(n)*t(n-1)) end: seq(a(n), n=0..100); CROSSREFS Cf. A020985, A190173, A213786, A213787. Sequence in context: A181295 A166299 A182508 * A329687 A321127 A222128 Adjacent sequences:  A213623 A213624 A213625 * A213627 A213628 A213629 KEYWORD sign,look AUTHOR Alois P. Heinz, Jun 23 2012 STATUS approved

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Last modified September 16 18:26 EDT 2021. Contains 347473 sequences. (Running on oeis4.)