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.

Showing 1-3 of 3 results.

A319388 Non-palindromic squares.

Original entry on oeis.org

16, 25, 36, 49, 64, 81, 100, 144, 169, 196, 225, 256, 289, 324, 361, 400, 441, 529, 576, 625, 729, 784, 841, 900, 961, 1024, 1089, 1156, 1225, 1296, 1369, 1444, 1521, 1600, 1681, 1764, 1849, 1936, 2025, 2116, 2209, 2304, 2401, 2500, 2601, 2704, 2809, 2916, 3025
Offset: 1

Views

Author

Seiichi Manyama, Sep 18 2018

Keywords

Comments

Intersection of A000290 and A029742. - Felix Fröhlich, Sep 18 2018

Crossrefs

Programs

  • Magma
    [n^2: n in [0..60] | not Intseq(n^2) eq Reverse(Intseq(n^2))]; // Vincenzo Librandi, Sep 19 2018
  • Maple
    ispali:= proc(n) local L;
    L:= convert(n,base,10);
    L = ListTools:-Reverse(L)
    end proc:
    remove(ispali, [seq(i^2,i=1..100)]); # Robert Israel, Sep 18 2018
  • Mathematica
     pb10Q[n_]:=!Module[{idn10=IntegerDigits[n, 10]}, idn10==Reverse[idn10]]; Select[Range[0, 3100]^2, pb10Q] (* Vincenzo Librandi, Sep 19 2018 *)
  • PARI
    terms(n) = my(i=0); for(k=0, oo, if(i==n, break); my(s=k^2, d=digits(s)); if(d!=Vecrev(d), print1(s, ", "); i++))
    /* Print initial 50 terms as follows */
    terms(50) \\ Felix Fröhlich, Sep 18 2018
    

A035124 Nonpalindromic cubes remaining cubic which written backwards: take the cube root of n, reverse its digits, cube that and the result is n with its digits reversed.

Original entry on oeis.org

1033364331, 1334633301, 1003303631331, 1331363033001, 1000330036301331, 1003033061330301, 1003333697667631, 1030331603303001, 1030637669664331, 1331036300330001, 1334669667360301, 1367667963333001, 1000033000363001331, 1000303030604030301, 1000333036964367631
Offset: 1

Views

Author

Patrick De Geest, Nov 15 1998

Keywords

Comments

Cubes with trailing zeros are excluded.

Examples

			1011^3 = 1033364331 -> 1334633301 = 1101^3.
1003333697667631 is included because its cube root, 100111, when reversed (i.e., 111001) and cubed yields 1367667963333001.
		

Crossrefs

Programs

  • PARI
    isok(n) = {if (ispower(n, 3, &k), dn = digits(n); if (Vecrev(dn) != dn, dk = Vecrev(digits(k)); rk = subst(Pol(dk, x), x, 10); digits(rk^3) == Vecrev(dn);););} \\ Michel Marcus, Oct 04 2015

Extensions

More terms from Seiichi Manyama, Sep 18 2018

A319441 Cubes of non-palindromic numbers.

Original entry on oeis.org

1000, 1728, 2197, 2744, 3375, 4096, 4913, 5832, 6859, 8000, 9261, 12167, 13824, 15625, 17576, 19683, 21952, 24389, 27000, 29791, 32768, 39304, 42875, 46656, 50653, 54872, 59319, 64000, 68921, 74088, 79507, 91125, 97336, 103823, 110592, 117649, 125000, 132651, 140608
Offset: 1

Views

Author

Seiichi Manyama, Sep 19 2018

Keywords

Comments

This is not a subsequence of A029742. - Bruno Berselli, Sep 19 2018

Examples

			2201^3 = 10662526601 is a term.
		

Crossrefs

Programs

  • Magma
    [n^3: n in [0..65] | Intseq(n) ne Reverse(Intseq(n))]; // Vincenzo Librandi, Sep 19 2018
    
  • Mathematica
    palQ[n_]:=Module[{idn=IntegerDigits[n]}, idn==Reverse[idn]]; DeleteCases[Range[10, 110], ?palQ]^3 (* _Vincenzo Librandi, Sep 19 2018 *)
    Select[Range[100],!PalindromeQ[#]&]^3 (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 13 2019 *)
  • PARI
    is_a029742(n)=my(d=digits(n)); d!=Vecrev(d) \\ after Charles R Greathouse IV in A029742
    terms(n) = my(i=0, x=1); while(1, if(i==n, break, if(is_a029742(x), print1(x^3, ", "); i++)); x++)
    /* Print initial 40 terms as follows */
    terms(40) \\ Felix Fröhlich, Sep 19 2018
    
  • Python
    def A319441(n):
        def f(x): return n+x//10**((l:=len(s:=str(x)))-(k:=l+1>>1))-(int(s[k-1::-1])>x%10**k)+10**(k-1+(l&1^1))-1
        m, k = n, f(n)
        while m != k:
            m, k = k, f(k)
        return m**3 # Chai Wah Wu, Jul 24 2024

Formula

a(n) = A029742(n)^3.
Showing 1-3 of 3 results.