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Search: id:A063395
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| 1, 3, 19, 131, 979, 7683, 62099, 511619, 4271699, 36018179, 305998099, 2615234691, 22459983059, 193665818115, 1675580699539, 14538892408451, 126467748738899, 1102484411211779, 9629327766561299, 84247346901823619
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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G.f.: 4x/sqrt(1-10x+9x^2) + (1-2x)/(1-x). - Ralf Stephan (ralf(AT)ark.in-berlin.de), Mar 23 2004
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PROGRAM
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(PARI) m=matrix(50, 50):for(i=1, 50, m[1, i]=1:m[i, 1]=1):for(i=2, 50, for(k=1, i, x=i-k+1: if(m[x, k]==0, m[x, k]=sum(n=2, k-1, m[x, n])+sum(n=2, x-1, m[n, k])+k+x-1))):for(n=1, 24, print1(m[n, n]", ")) (from R. Stephan)
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CROSSREFS
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Equals 4*A084771(n-1) - 1, n>0.
Sequence in context: A058860 A074568 A074713 this_sequence A074567 A091346 A035086
Adjacent sequences: A063392 A063393 A063394 this_sequence A063396 A063397 A063398
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KEYWORD
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nonn
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AUTHOR
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Floor van Lamoen (fvlamoen(AT)hotmail.com), Jul 16 2001
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EXTENSIONS
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More terms from Ralf Stephan (ralf(AT)ark.in-berlin.de), Mar 23 2004
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