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A288082
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a(n) is the number of rooted maps with n edges and 2 faces on an orientable surface of genus 2.
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9
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483, 15018, 258972, 3288327, 34374186, 313530000, 2583699888, 19678611645, 140725699686, 955708437684, 6216591472728, 38985279745230, 236923660397172, 1401097546161936, 8089830217844928, 45732525474843801, 253705943922820830, 1383896652090932364, 7434748752218650632, 39394773780853063650
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OFFSET
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5,1
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LINKS
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MATHEMATICA
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Q[0, 1, 0] = 1; Q[n_, f_, g_] /; n < 0 || f < 0 || g < 0 = 0;
Q[n_, f_, g_] := Q[n, f, g] = 6/(n + 1) ((2 n - 1)/3 Q[n - 1, f, g] + (2 n - 1)/3 Q[n - 1, f - 1, g] + (2 n - 3) (2 n - 2) (2 n - 1)/12 Q[n - 2, f, g - 1] + 1/2 Sum[l = n - k; Sum[v = f - u; Sum[j = g - i; Boole[l >= 1 && v >= 1 && j >= 0] (2 k - 1) (2 l - 1) Q[k - 1, u, i] Q[l - 1, v, j], {i, 0, g}], {u, 1, f}], {k, 1, n}]);
a[n_] := Q[n, 2, 2];
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PROG
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(PARI)
A000108_ser(N) = my(x='x+O('x^(N+1))); (1 - sqrt(1-4*x))/(2*x);
3*y*(y-1)^5*(7*y^4 + 294*y^3 + 309*y^2 - 547*y + 98)/(y-2)^14;
};
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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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