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Search: id:A125004
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| A125004 |
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a(0) = 9; for n>0, a(n) is determined by the rule that the concatenation of the leading terms of the difference triangle is the same as the concatenation of the digits of the sequence. |
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2
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| 9, 10, 11, 13, 18, 30, 59, 129, 299, 717, 1741, 4183, 9781, 22123, 48516, 103856, 218683, 455839, 944616, 1950404, 4016865, 8257883, 16962086, 34853986, 71735687, 148017585, 306239910, 634872376, 1316958592, 2728411246
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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a(0) = 9; binomial transform of sequence gives successive digits of sequence.
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LINKS
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N. J. A. Sloane, Transforms
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MAPLE
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revert := proc(n) local Linv, i, L ; L := convert(n, base, 10) ; Linv := [] ; for i from 1 to nops(L) do Linv := [op(Linv), op(-i, L)] ; od ; RETURN(Linv) ; end: A125004 := proc(nmax) local ldigs, T, diag, row ; T := array(1..nmax, 1..nmax) ; ldigs := [9, 1, 0] ; T[1, 1] := ldigs[1] ; for diag from 2 to nmax do T[diag, 1] := ldigs[diag] ; for row from diag-1 to 1 by -1 do T[row, diag-row+1] := T[row, diag-row]+T[row+1, diag-row] ; od ; if diag > 2 then ldigs := [op(ldigs), op(revert(T[1, diag])) ] ; fi ; od ; RETURN(T) ; end : nmax := 50 : T := A125004(nmax) : for i from 1 to nmax do printf("%d, ", T[1, i]) ; od ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 10 2007
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CROSSREFS
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Cf. A125588, A125003, A125591.
Sequence in context: A031047 A120193 A134534 this_sequence A085514 A086446 A045522
Adjacent sequences: A125001 A125002 A125003 this_sequence A125005 A125006 A125007
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KEYWORD
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nonn,easy,base
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Jan 08 2007
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 10 2007
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