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.

A014563 a(n+1) is the smallest number > a(n) such that the digits of a(n)^2 are all (with multiplicity) contained in the digits of a(n+1)^2, with a(0)=1.

Original entry on oeis.org

1, 4, 13, 14, 31, 36, 54, 96, 113, 311, 487, 854, 1036, 1277, 1646, 3214, 8351, 10456, 11414, 11536, 11563, 17606, 17813, 30287, 36786, 41544, 54927, 56547, 56586, 57363, 62469, 62634, 72813, 72897, 76944, 78345, 95061, 97944, 100963, 101944
Offset: 0

Views

Author

Marc Paulhus, Jan 29 2002

Keywords

Comments

Probably infinite. - David W. Wilson, Jan 29 2002

Examples

			13^2 = 169 and 14 is the next smallest number whose square (in this case 196) contains the digits 1,6,9.
		

Crossrefs

If "contained in" is replaced by "properly contained in" we get A065297.

Programs

  • Haskell
    import Data.List ((\\))
    a014563 n = a014563_list !! n
    a014563_list = 1 : f 1 (drop 2 a000290_list) where
       f x (q:qs) | null $ xs \\ (show q) = y : f y qs
                  | otherwise             = f x qs
                  where y = a000196 q; xs = show (x * x)
    -- Reinhard Zumkeller, Nov 22 2012
  • Mathematica
    snd[n_]:=Module[{k=n+1},While[!AllTrue[Select[Transpose[{DigitCount[n^2],
    DigitCount[k^2]}],#[[1]]>0&],#[[1]]<=#[[2]]&],k++];k]; NestList[ snd,1,40] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Sep 21 2016 *)

A066825 a(1) = 1; set of digits of a(n)^2 is a subset of the set of digits of a(n+1)^2.

Original entry on oeis.org

1, 4, 13, 14, 31, 36, 54, 96, 113, 311, 487, 854, 1036, 1277, 1646, 3214, 3267, 3723, 4047, 4554, 4896, 5376, 10136, 13147, 13268, 16549, 20513, 21877, 25279, 26152, 27209, 28582, 31723, 32043, 32286, 33144, 35172, 35337, 35757, 35853
Offset: 1

Views

Author

David W. Wilson, Feb 05 2002

Keywords

Comments

Probably infinite and dense over Z+.

Crossrefs

Programs

  • Haskell
    import Data.List ((\\))
    a066825 n = a066825_list !! (n-1)
    a066825_list = 1 : f 1 (drop 2 a000290_list) where
       f x (q:qs) | all (`elem` show q) xs = y : f y qs
                  | otherwise              = f x qs
                  where y = a000196 q; xs = show (x * x)
    -- Reinhard Zumkeller, Nov 22 2012

A383214 a(n) = A067434(n) - A383213(n).

Original entry on oeis.org

1, 1, 0, 1, -1, 1, 0, 1, 0, 0, 0, 0, 0, -1, 1, 1, -1, 1, -1, 1, 0, 0, -1, 1, 0, 0, -1, 1, 1, -1, 0, 1, 0, 0, 0, 0, 0, 1, -2, 1, -1, 1, 0, -1, 1, 0, -1, 1, 0, 0, 0, 0, -1, 2, -1, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 1, 0, 0, 0, 0, -1, 1, 0, -1, 1, -1, 1, 0, -1, 1
Offset: 1

Views

Author

Clark Kimberling, Apr 19 2025

Keywords

Comments

Least n such that a(n) = -3 is 7055; least n such than a(n) = 3 is 740.

Crossrefs

Programs

  • Mathematica
    u = Table[PrimeNu[Binomial[2 n, n]], {n,  200}]     (* A067434 *)
    v = Table[PrimeNu[Binomial[2 n, n + 1]], {n,  200}] (* A383213 *)
    u - v
Showing 1-3 of 3 results.