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A258682 Remove from n^2 all digits of n from left to right, in decimal representation. 6
0, 0, 4, 9, 16, 2, 3, 49, 64, 81, 0, 2, 44, 69, 96, 22, 25, 289, 324, 36, 40, 44, 484, 59, 576, 6, 76, 9, 74, 841, 90, 96, 104, 1089, 1156, 122, 129, 169, 1444, 1521, 160, 681, 176, 189, 1936, 202, 211, 2209, 230, 201, 20, 260, 704, 2809, 2916, 302, 313 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

a(A029783(n)) = A029783(n)^2; a(A189056(n)) < A189056(n)^2;

a(A178501(n)) = 0.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

EXAMPLE

.    n   n^2 |  a(n)

. -----------+------

.   20   400 |    40

.   21   441 |    44

.   22   484 |   484

.   23   529 |    59

.   24   576 |   576

.   25   625 |     6

.   26   676 |    76  not 67, as digits of n are to be removed

.   27   729 |     9                                  from left to right

.   28   784 |    74

.   29   841 |   841

.   30   900 |    90  .

MATHEMATICA

a[n_]:=Module[{idn=IntegerDigits[n], idnn=IntegerDigits[n^2], idn1},

idn1=DeleteCases[idn, m_/; MemberQ[Complement[idn, idnn], m]];

Do[If[First[Position[idnn, idn1[[i]]]]!= {}, idnn=Delete[idnn, First[Position[idnn, idn1[[i]]]]]],

{i, 1, Length[idn1]}]; FromDigits[idnn]]//Quiet;

a/@Range[0, 56] (* Ivan N. Ianakiev, Jun 11 2015 *)

PROG

(Haskell)

import Data.List (delete)

a258682 n = read ('0' : minus (show (n ^ 2)) (show n)) :: Int  where

   minus [] _  = []

   minus us [] = us

   minus (u:us) vs | elem u vs = minus us $ delete u vs

                   | otherwise = u : minus us vs

CROSSREFS

Cf. A000290, A029783, A189056, A178501.

Sequence in context: A276191 A007893 A070446 * A070445 A070444 A120866

Adjacent sequences:  A258679 A258680 A258681 * A258683 A258684 A258685

KEYWORD

nonn,base,look

AUTHOR

Reinhard Zumkeller, Jun 07 2015

STATUS

approved

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Last modified January 18 03:13 EST 2019. Contains 319260 sequences. (Running on oeis4.)