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 A187122 A diagonal of triangle A187120. 4
 1, 9, 81, 855, 10758, 159633, 2750067, 54178485, 1204443432, 29871630837, 818490738402, 24571782872034, 802459134168208, 28332664539686670, 1075700621922471621, 43710289920461797346, 1893011243289589171122 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,2 COMMENTS Definition of triangle: A187120(n,k) = [y^k] R_{n-1}(y+y^2) for k=3..n, n>3, where R_n(y) is the n-th row polynomial starting with R_3(y)=y^3. LINKS FORMULA Equals column 2 in the matrix cube of triangle A135080. PROG (PARI) {a(n)=local(Rn=y^3); for(m=3, n+1, Rn=subst(truncate(Rn), y, y+y^2+O(y^m))); polcoeff(Rn, n, y)} CROSSREFS Cf. A187120, A135083, A187121, A187123, A187124. Sequence in context: A077364 A077486 A233021 * A113361 A180737 A068881 Adjacent sequences: A187119 A187120 A187121 * A187123 A187124 A187125 KEYWORD nonn AUTHOR Paul D. Hanna, Mar 08 2011 STATUS approved

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Last modified March 27 18:55 EDT 2023. Contains 361575 sequences. (Running on oeis4.)