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A047131
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a(n) = Sum_{i=0..n} A047130(i, n-i).
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2
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1, 2, 3, 6, 10, 20, 35, 70, 140, 252, 504, 932, 1864, 3493, 6986, 13972, 26265, 52530, 100168, 200336, 384573, 769146, 1538292, 2950530, 5901060, 11422700, 22845400, 44403564, 88807128, 177614256, 344644881, 689289762, 1346117062
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listen;
history;
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internal format)
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OFFSET
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0,2
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LINKS
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PROG
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(PARI) A(h, k=h)={my(M=matrix(h+1, k+1, i, j, 1)); for(h=1, h, for(k=1, k, M[1+h, 1+k] = M[h, 1+k] + if(4*k>3*h && 4*(k-1)<3*h, 0, M[1+h, k]))); M}
seq(n)={my(T=A(n)); vector(#T, k, sum(i=0, k-1, T[1+i, k-i]))} \\ Andrew Howroyd, Jan 19 2020
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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