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.

A093882 Sum of all the numbers formed by deleting one digit from n.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 8, 9, 10, 11, 12, 13, 14, 15
Offset: 0

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Author

Amarnath Murthy, Apr 22 2004

Keywords

Comments

Subsidiary sequence: Sum of the numbers formed by deleting all possible strings touching one end ( containing at least one of the LSB or MSB). A071980(123) = 123 + 12 + 1 + 23 + 3 = 162. A071980(1234) = 1 + 12 + 123 + 1234 + 234 + 34 + 4 = 1642.
This allows leading zeros are after deletion. If these are forbidden, the first change would be a(101) = 21 instead of 22. - Franklin T. Adams-Watters, Jul 27 2006

Examples

			a(123) = 12 + 13 + 23 = 48. [corrected by _Harvey P. Dale_, Jul 24 2017]
		

Crossrefs

Cf. A007953.

Programs

  • Maple
    read("transforms"):
    A093882 := proc(n)
        local a,dgs,d,dgsred ;
        a := 0 ;
        dgs := convert(n,base,10) ;
        for d from 1 to nops(dgs) do
            [op(1..d-1,dgs),op(d+1..nops(dgs),dgs)] ;
            a := a+digcatL(%) ;
        end do:
        a ;
    end proc: # R. J. Mathar, May 06 2019
    # second Maple program:
    a:= n-> (s-> add(parse(cat("0", s[..i-1],
             s[i+1..])), i=1..length(s)))(""||n):
    seq(a(n), n=0..123);  # Alois P. Heinz, May 06 2019
  • Mathematica
    sn[n_]:=Module[{idn=IntegerDigits[n]},Total[FromDigits/@Table[ Delete[ idn,i],{i,Length[idn]}]]]; Array[sn,90,0] (* Harvey P. Dale, Jul 24 2017 *)
  • Python
    def a(n): s=str(n); return sum(int(s[:i]+s[i+1:]) for i in range(len(s))) if n > 9 else 0
    print([a(n) for n in range(88)]) # Michael S. Branicky, Oct 27 2023

Extensions

Corrected and extended by Franklin T. Adams-Watters, Jul 27 2006
Offset corrected by Alois P. Heinz, May 06 2019