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.

A243658 a(0)=0; thereafter a(n) = noz(n+a(n-1)), where noz(n) = A004719(n).

Original entry on oeis.org

0, 1, 3, 6, 1, 6, 12, 19, 27, 36, 46, 57, 69, 82, 96, 111, 127, 144, 162, 181, 21, 42, 64, 87, 111, 136, 162, 189, 217, 246, 276, 37, 69, 12, 46, 81, 117, 154, 192, 231, 271, 312, 354, 397, 441, 486, 532, 579, 627, 676, 726, 777, 829, 882, 936, 991, 147, 24, 82, 141, 21, 82, 144, 27, 91, 156, 222, 289
Offset: 0

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Author

N. J. A. Sloane, Jun 11 2014

Keywords

Comments

Zeroless analog of triangular numbers.

Crossrefs

Row n = 3 of A373169.

Programs

  • Maple
    noz:=proc(n) local a,t1,i,j; a:=0; t1:=convert(n,base,10); for i from 1 to nops(t1) do j:=t1[nops(t1)+1-i]; if j <> 0 then a := 10*a+j; fi; od: a; end;
    t1:=[0]; for n from 1 to 50 do t1:=[op(t1),noz(n+t1[n])]; od: t1;
  • Mathematica
    noz[n_] := FromDigits[DeleteCases[IntegerDigits[n], 0]];
    Block[{n = 0}, NestList[noz[++n+#] &, 0, 100]] (* Paolo Xausa, Apr 17 2024 *)
  • Python
    from itertools import count, islice
    def noz(n): return int(str(n).replace("0", ""))
    def agen(): # generator of terms
        yield (an:=0)
        yield from (an:=noz(n+an) for n in count(1))
    print(list(islice(agen(), 68))) # Michael S. Branicky, Jul 02 2024