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 1-10 of 13 results. Next

A065733 Largest square <= n^3.

Original entry on oeis.org

0, 1, 4, 25, 64, 121, 196, 324, 484, 729, 961, 1296, 1681, 2116, 2704, 3364, 4096, 4900, 5776, 6724, 7921, 9216, 10609, 12100, 13689, 15625, 17424, 19600, 21904, 24336, 26896, 29584, 32761, 35721, 39204, 42849, 46656, 50625, 54756, 59049, 63504
Offset: 0

Views

Author

Labos Elemer, Nov 15 2001

Keywords

Examples

			a(10) = 961, as 961 = 31^2 is the largest square <= 1000 = 10^3.
		

Crossrefs

Programs

  • Haskell
    a065733 n = head [x | x <- reverse [0.. n^3], a010052 x == 1] -- Reinhard Zumkeller, Oct 10 2013
  • Mathematica
    Table[Floor[Sqrt[w^3]//N]^2, {w, 1, 50}]
  • PARI
    A065733(n)=sqrtint(n^3)^2  \\ M. F. Hasler, Oct 05 2013
    

Formula

a(n) + A077116(n) = n^3.
a(n) = A048760(n^3).
n^3 - 2*n^(3/2) <= a(n) <= n^3. - Charles R Greathouse IV, Dec 05 2022
a(n) = A000093(n)^2. - Amiram Eldar, Jul 14 2024

A065741 Largest square <= sum of squares of divisors of n.

Original entry on oeis.org

1, 4, 9, 16, 25, 49, 49, 81, 81, 121, 121, 196, 169, 225, 256, 324, 289, 441, 361, 529, 484, 576, 529, 841, 625, 841, 784, 1024, 841, 1296, 961, 1296, 1156, 1444, 1296, 1849, 1369, 1764, 1681, 2209, 1681, 2500, 1849, 2500, 2304, 2601, 2209, 3364, 2401
Offset: 1

Views

Author

Labos Elemer, Nov 15 2001

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Floor[Sqrt[DivisorSigma[2, w]]//N]^2, {w, 1, 100}]
  • PARI
    a(n) = { sqrtint(sigma(n,2))^2 } \\ Harry J. Smith, Oct 29 2009

Formula

a(n) = A048760(A001157(n)).

A257053 Primes in enhanced squares representation, cf. A256913.

Original entry on oeis.org

2, 3, 4, 1, 4, 3, 9, 2, 9, 4, 16, 1, 16, 3, 16, 4, 3, 25, 4, 25, 4, 2, 36, 1, 36, 4, 1, 36, 4, 3, 36, 9, 2, 49, 4, 49, 9, 1, 49, 9, 3, 64, 3, 64, 4, 3, 64, 9, 64, 9, 4, 2, 81, 2, 81, 4, 3, 1, 81, 16, 100, 1, 100, 3, 100, 4, 3, 100, 9, 100, 9, 4, 121, 4, 2
Offset: 1

Views

Author

Reinhard Zumkeller, Apr 15 2015

Keywords

Comments

A257070(n) = length of n-th row;
T(n,k) = A256913(A000040(n),k), k = 0..A257070(n)-1;
T(n,0) = A065730(n) for n > 2;
T(n,A257071(n)-1) = A257070(n).

Examples

			.   n | prime(n) |  ESR, row sum = prime(n)
.  ---+----------+-------------------------
.   1 |        2 |  [2]
.   2 |        3 |  [3]
.   3 |        5 |  [4, 1]
.   4 |        7 |  [4, 3]
.   5 |       11 |  [9, 2]
.   6 |       13 |  [9, 4]
.   7 |       17 |  [16, 1]
.   8 |       19 |  [16, 3]
.   9 |       23 |  [16, 4, 3]
.  10 |       29 |  [25, 4]
.  11 |       31 |  [25, 4, 2]
.  12 |       37 |  [36, 1]
.  13 |       41 |  [36, 4, 1]
.  14 |       43 |  [36, 4, 3]
.  15 |       47 |  [36, 9, 2]
.  16 |       53 |  [49, 4]
.  17 |       59 |  [49, 9, 1]
.  18 |       61 |  [49, 9, 3]
.  19 |       67 |  [64, 3]
.  20 |       71 |  [64, 4, 3]
.  21 |       73 |  [64, 9]
.  22 |       79 |  [64, 9, 4, 2]
.  23 |       83 |  [81, 2]
.  24 |       89 |  [81, 4, 3, 1]
.  25 |       97 |  [81, 16]
		

Crossrefs

%Cf. A256913, A000040, A065730, A257070 (traces), A257071 (row lengths).

Programs

  • Haskell
    a257053 n k = a257053_tabf !! (n-1) !! k
    a257053_row n = a257053_tabf !! (n-1)
    a257053_tabf = map (a256913_row . fromIntegral) a000040_list

A065731 Largest square <= n!.

Original entry on oeis.org

1, 1, 1, 4, 16, 100, 676, 4900, 40000, 362404, 3625216, 39904489, 478996996, 6226945921, 87177877081, 1307672296225, 20922784184449, 355687416544329, 6402373660047556, 121645099966283776, 2432902006216007824, 51090942169052381124, 1124000727752683686724
Offset: 0

Views

Author

Labos Elemer, Nov 15 2001

Keywords

Crossrefs

Programs

Formula

a(n) = floor(sqrt(n!))^2.
a(n) = A048760(A000142(n)).

Extensions

Offset changed from 1 to 0 by Harry J. Smith, Oct 28 2009

A065732 Largest square <= 2^n.

Original entry on oeis.org

1, 4, 4, 16, 25, 64, 121, 256, 484, 1024, 2025, 4096, 8100, 16384, 32761, 65536, 131044, 262144, 524176, 1048576, 2096704, 4194304, 8386816, 16777216, 33547264, 67108864, 134212225, 268435456, 536848900, 1073741824, 2147395600, 4294967296, 8589767761, 17179869184
Offset: 1

Views

Author

Labos Elemer, Nov 15 2001

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Floor[Sqrt[2^w]//N]^2, {w, 1, 50}]
  • PARI
    a(n) = { sqrtint(2^n)^2 } \\ Harry J. Smith, Oct 28 2009

Formula

a(n) = A048760(A000079(n)) = A048760(2^n).

A065736 Largest square <= 10^n.

Original entry on oeis.org

9, 100, 961, 10000, 99856, 1000000, 9998244, 100000000, 999950884, 10000000000, 99999515529, 1000000000000, 9999995824729, 100000000000000, 999999961946176, 10000000000000000, 99999999989350756, 1000000000000000000, 9999999998935075600, 100000000000000000000, 999999999956753113201
Offset: 1

Views

Author

Labos Elemer, Nov 15 2001

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Floor[Sqrt[10^n]]^2,{n,20}] (* Harvey P. Dale, Dec 04 2014 *)
  • PARI
    a(n) = { sqrtint(10^n)^2 } \\ Harry J. Smith, Oct 28 2009

Formula

a(n) = A048760(A011557(n)) = A048760(10^n).

A065734 Largest square <= sigma(n).

Original entry on oeis.org

1, 1, 4, 4, 4, 9, 4, 9, 9, 16, 9, 25, 9, 16, 16, 25, 16, 36, 16, 36, 25, 36, 16, 49, 25, 36, 36, 49, 25, 64, 25, 49, 36, 49, 36, 81, 36, 49, 49, 81, 36, 81, 36, 81, 64, 64, 36, 121, 49, 81, 64, 81, 49, 100, 64, 100, 64, 81, 49, 144, 49, 81, 100, 121, 81, 144, 64, 121, 81, 144
Offset: 1

Views

Author

Labos Elemer, Nov 15 2001

Keywords

Crossrefs

Programs

Formula

a(n) = A048760(A000203(n)).

Extensions

Previous Mathematica program replaced by Harvey P. Dale, Oct 05 2015

A065735 Largest square <= product of first n primes.

Original entry on oeis.org

1, 4, 25, 196, 2304, 29929, 509796, 9696996, 223084096, 6469628356, 200559769921, 7420737154609, 304250260158441, 13082761295250201, 614889781233144561, 32589158470911505225, 1922760350143213168900
Offset: 1

Views

Author

Labos Elemer, Nov 15 2001

Keywords

Crossrefs

Programs

  • Mathematica
    Floor[Sqrt[#]]^2&/@FoldList[Times,Prime[Range[20]]] (* Harvey P. Dale, Jan 13 2024 *)
  • PARI
    { m=1; for (n=1, 100, m*=prime(n); a=sqrtint(m)^2; write("b065735.txt", n, " ", a) ) } \\ Harry J. Smith, Oct 28 2009

Formula

a(n) = A048760(A002110(n)).

A065737 Largest square <= binomial(n,2).

Original entry on oeis.org

0, 1, 1, 4, 9, 9, 16, 25, 36, 36, 49, 64, 64, 81, 100, 100, 121, 144, 169, 169, 196, 225, 225, 256, 289, 324, 324, 361, 400, 400, 441, 484, 484, 529, 576, 625, 625, 676, 729, 729, 784, 841, 900, 900, 961, 1024, 1024, 1089, 1156, 1225, 1225, 1296, 1369, 1369, 1444
Offset: 1

Views

Author

Labos Elemer, Nov 15 2001

Keywords

Crossrefs

Programs

  • Mathematica
    Floor[Sqrt[#]]^2&/@Binomial[Range[50],2] (* Harvey P. Dale, Feb 28 2020 *)
  • PARI
    a(n) = { sqrtint(binomial(n, 2))^2 } \\ Harry J. Smith, Oct 28 2009

Formula

a(n) = A048760(binomial(n,2)).
a(n) = A061288(n-1)^2 = A000290(A061288(n-1)) for n>=2. - Alois P. Heinz, Nov 07 2024

A065738 Largest square <= binomial(2n,n).

Original entry on oeis.org

1, 4, 16, 64, 225, 900, 3364, 12769, 48400, 184041, 703921, 2702736, 10394176, 40106889, 155102116, 601034256, 2333566249, 9075039169, 35345128009, 137845868176, 538256995600, 2104098203601, 8233427666025, 32247599617809
Offset: 1

Views

Author

Labos Elemer, Nov 15 2001

Keywords

Crossrefs

Programs

  • PARI
    a(n) = { sqrtint(binomial(2*n, n))^2 } \\ Harry J. Smith, Oct 29 2009

Formula

a(n) = A048760(A000984(n)).

Extensions

Terms corrected and extended by Harry J. Smith, Oct 29 2009
Showing 1-10 of 13 results. Next