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A125004 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. 2
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; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
a(0) = 9; binomial transform of sequence gives successive digits of sequence.
LINKS
N. J. A. Sloane, Transforms
MAPLE
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, Jan 10 2007
CROSSREFS
Sequence in context: A031047 A120193 A134534 * A085514 A086446 A168042
KEYWORD
nonn,easy,base
AUTHOR
N. J. A. Sloane, Jan 08 2007
EXTENSIONS
More terms from R. J. Mathar, Jan 10 2007
STATUS
approved

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Last modified February 21 12:33 EST 2024. Contains 370235 sequences. (Running on oeis4.)