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.

A169894 Table of carryless sums i + j, i>=0, j>=0, read by antidiagonals.

Original entry on oeis.org

0, 1, 1, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 11, 11, 1, 1, 1, 1, 1, 1, 1, 1, 11, 11, 12, 12, 12, 2, 2, 2, 2, 2, 2, 2, 12, 12, 12
Offset: 0

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Examples

			Table begins:
  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 ...
  1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 11, 12, 13, 14, 15, 16 ...
  2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 12, 13, 14, 15, 16, 17 ...
  3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 13, 14, 15, 16, 17, 18 ...
  4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 14, 15, 16, 17, 18, 19 ...
  ...
		

Crossrefs

Cf. A004520 (diagonal), A059692 (carryless products).

Programs

  • Maple
    A169894 := proc(a,b)
        local adigs,bdigs,cdigs ;
        adigs := convert(a,base,10) ;
        bdigs := convert(b,base,10) ;
        len := max(nops(adigs),nops(bdigs)) ;
        adigs := [op(adigs),seq(0,d=1..len-nops(adigs))] ;
        bdigs := [op(bdigs),seq(0,d=1..len-nops(bdigs))] ;
        cdigs := [] ;
        for d from 1 to len do
            cdigs := [op(cdigs),A010879(op(d,adigs)+op(d,bdigs))] ;
        end do:
        add(op(d,cdigs)*10^(d-1),d=1..len) ;
    end proc: # R. J. Mathar, Jul 12 2013
  • Mathematica
    len[num_]:=Length[IntegerDigits[num]]; digit[num_, d_]:=Part[IntegerDigits[num], d]; T[i_, j_] := FromDigits[Reverse[CoefficientList[PolynomialMod[Sum[digit[i, c]*x^(len[i]-c), {c, len[i]}]+Sum[digit[j, r]*x^(len[j]-r), {r, len[j]}], 10], x]]]; Table[T[i - j, j], {i, 0, 12}, {j, 0, i}] (* Stefano Spezia, Dec 20 2023 *)