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A136650
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Self-convolution of A006125(n) = 2^{n(n-1)/2}.
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0
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1, 2, 5, 20, 148, 2208, 67904, 4264960, 541216768, 137984868352, 70507295670272, 72128242290524160, 147646152060442771456, 604610628447525580832768, 4952364915780360673188380672, 81134591384874923825347187179520
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = Sum_{k=0..n} 2^{ k(k-1)/2 + (n-k)(n-k-1)/2 }.
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PROG
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(PARI) a(n)=sum(k=0, n, 2^(k*(k-1)/2 + (n-k)*(n-k-1)/2))
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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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