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A277411
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Column 1 of triangle A277410.
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3
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0, 3, 13, 38, 94, 213, 459, 960, 1972, 4007, 8089, 16266, 32634, 65385, 130903, 261956, 524080, 1048347, 2096901, 4194030, 8388310, 16776893, 33554083, 67108488, 134217324, 268435023, 536870449, 1073741330, 2147483122, 4294966737, 8589933999, 17179868556, 34359737704, 68719476035, 137438952733, 274877906166, 549755813070, 1099511626917, 2199023254651, 4398046510160
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OFFSET
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1,2
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LINKS
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FORMULA
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G.f.: x^2*(3-2*x) / ((1-x)^3*(1-2*x)).
a(n) = 5*a(n-1)-9*a(n-2)+7*a(n-3)-2*a(n-4) for n>4.
a(n) = (8*(2^n-1)-n*(n+7))/2. (End)
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PROG
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(PARI) {A277410(n, k) = my(A=x); for(i=1, n, A = x + subst(intformal(A +x*O(x^n)), x, y*A + (1-y)*x ) ); n!*polcoeff(polcoeff(A, n, x), k, y)}
for(n=1, 30, print1(A277410(n+1, 1), ", "));
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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