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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
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
Sequence in context: A276191 A007893 A070446 * A070445 A070444 A120866
KEYWORD
nonn,base,look
AUTHOR
Reinhard Zumkeller, Jun 07 2015
STATUS
approved

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Last modified May 23 22:02 EDT 2024. Contains 372765 sequences. (Running on oeis4.)