cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A134647 Let a(1) = 0, a(2) = 1; and a(n) = a(n-1) + [the two-digit integer split by the comma which separates a(n-1) and a(n-2)].

Original entry on oeis.org

0, 1, 2, 14, 35, 78, 135, 216, 268, 330, 413, 417, 451, 525, 540, 595, 600, 656, 662, 728, 755, 842, 900, 929, 938, 1037, 1118, 1189, 1270, 1361, 1362, 1373, 1394, 1425, 1466, 1517, 1578, 1649, 1730, 1821, 1822, 1833, 1854, 1885, 1926, 1977
Offset: 1

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Author

N. J. A. Sloane, Oct 17 2009, based on a posting to the Sequence Fans Mailing List by Eric Angelini, Oct 15 2009

Keywords

Examples

			135 = 78 + 57, since the comma in 35,78 splits the number 57.
		

Crossrefs

Cf. A121805, A367357 (first differences).

Programs

  • Maple
    # to compute the first M terms, from N. J. A. Sloane, Nov 20 2023
    Ldigit:=proc(n) local v; v:=convert(n, base, 10); v[-1]; end;
    M:=100;
    s:=[0,1]; i:=0; j:=1;
    for m from 2 to M do
    k := j + 10*(i mod 10) + Ldigit(j); s:=[op(s),k]; i:=j; j:=k; od:
    s;
  • Mathematica
    a[1]=0;a[2]=1;
    a[n_]:=a[n]=a[n-1]+10 Mod[a[n-2],10]+IntegerDigits[a[n-1]][[1]];
    Table[a[k],{k,100}]
    nxt[{a_,b_}]:={b,b+10IntegerDigits[a][[-1]]+First[IntegerDigits[b]]}; NestList[ nxt,{0,1},50][[All,1]] (* Harvey P. Dale, Jul 01 2020 *)

Extensions

Corrected and extended with Mma code by Farideh Firoozbakht, Oct 15 2009