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 1-6 of 6 results.

A145445 a(n) = the smallest square > n-th prime.

Original entry on oeis.org

4, 4, 9, 9, 16, 16, 25, 25, 25, 36, 36, 49, 49, 49, 49, 64, 64, 64, 81, 81, 81, 81, 100, 100, 100, 121, 121, 121, 121, 121, 144, 144, 144, 144, 169, 169, 169, 169, 169, 196, 196, 196, 196, 196, 225, 225, 225, 225, 256, 256, 256, 256, 256, 256, 289, 289, 289, 289
Offset: 1

Views

Author

Zak Seidov, Oct 10 2008

Keywords

Crossrefs

Cf. A104103.
Cf. A000040, A000290, A014085 (run lengths), A245508.

Programs

  • Haskell
    a145445 n = a145445_list !! (n-1)
    a145445_list = f a000040_list $ drop 2 a000290_list where
       f ps'@ (p:ps) xs'@(x:xs) = if p < x then x : f ps xs' else f ps' xs
    -- Reinhard Zumkeller, Jul 25 2014
    
  • Mathematica
    Table[Ceiling[Prime[n]^(1/2)]^2,{n,100}]
  • Python
    from sympy import prime, integer_nthroot
    def a(n): return (integer_nthroot(prime(n), 2)[0]+1)**2
    print([a(n) for n in range(1, 59)]) # Michael S. Branicky, Apr 04 2021

Formula

a(n) = A104103(n)^2.

A103416 a(n) = n - ceiling(sqrt(prime(n))).

Original entry on oeis.org

-1, 0, 0, 1, 1, 2, 2, 3, 4, 4, 5, 5, 6, 7, 8, 8, 9, 10, 10, 11, 12, 13, 13, 14, 15, 15, 16, 17, 18, 19, 19, 20, 21, 22, 22, 23, 24, 25, 26, 26, 27, 28, 29, 30, 30, 31, 32, 33, 33, 34, 35, 36, 37, 38, 38, 39, 40, 41, 42, 43, 44, 44, 45, 46, 47, 48, 48, 49, 50, 51, 52, 53, 53, 54, 55
Offset: 0

Views

Author

Giovanni Teofilatto, Mar 21 2005

Keywords

Crossrefs

Cf. A104103.

Programs

  • Mathematica
    Table[n - Ceiling[ Sqrt[ Prime[ n]]], {n, 75}] (* Robert G. Wilson v, Mar 24 2005 *)
  • Python
    from math import isqrt
    from sympy import prime
    def A103416(n): return n-isqrt(prime(n+1)) # Chai Wah Wu, Jul 29 2022

Formula

a(n) = n - A104103(n). - Michel Marcus, Jul 30 2022

Extensions

More terms from Robert G. Wilson v, Mar 24 2005

A145447 a(n) = the smallest square (and/or cube) > n-th prime.

Original entry on oeis.org

4, 4, 8, 8, 16, 16, 25, 25, 25, 36, 36, 49, 49, 49, 49, 64, 64, 64, 81, 81, 81, 81, 100, 100, 100, 121, 121, 121, 121, 121, 144, 144, 144, 144, 169, 169, 169, 169, 169, 196, 196, 196, 196, 196, 216, 216, 216, 225, 256, 256, 256, 256, 256, 256, 289, 289, 289, 289
Offset: 1

Views

Author

Zak Seidov, Oct 10 2008

Keywords

Comments

a(n) = min(A145445(n), A145446(n) )= min ([A104103(n)]^2, [A104147(n)]^3)

Crossrefs

Programs

  • Mathematica
    Table[Min[{Ceiling[Prime[n]^(1/3)]^3,Ceiling[Prime[n]^(1/2)]^2}],{n,100}]

A145449 Numbers n such that A145445(n) = A145446(n).

Original entry on oeis.org

16, 17, 18, 123, 124, 125, 126, 127, 128, 129, 550, 551, 552, 553, 554, 555, 556, 557, 558, 559, 560, 561, 562, 563, 564, 1797, 1798, 1799, 1800, 1801, 1802, 1803, 1804, 1805, 1806, 1807, 1808, 1809, 1810, 1811, 1812, 1813, 1814, 1815, 1816, 1817, 1818
Offset: 1

Views

Author

Zak Seidov, Oct 10 2008

Keywords

Comments

Numbers n such that s(n), the smallest square > n-th prime, equals q(n), the smallest cube > n-th prime, s(n) = A145445(n), q(n) = A145446(n).

Crossrefs

Programs

  • Mathematica
    Do[If[Ceiling[Prime[n]^(1/3)]^3 == Ceiling[Prime[n]^(1/2)]^2,Print[n]],{n,10000}]

A166127 Minimum value of j such that floor(j^2 / prime(n)) > 0.

Original entry on oeis.org

0, 2, 3, 3, 4, 4, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 9, 10, 10, 10, 11, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 19, 19, 19, 19, 19, 19, 20, 20, 20, 20, 20
Offset: 1

Views

Author

Keywords

Comments

Essentially the same as A104103. - R. J. Mathar, Jul 21 2015

Crossrefs

Programs

  • Mathematica
    Join[{0},Table[Ceiling[Sqrt[p]],{p,Prime[Range[2,80]]}]] (* Harvey P. Dale, Oct 10 2020 *)

A123241 Number of squares < lesser of twin primes.

Original entry on oeis.org

2, 3, 4, 5, 6, 7, 8, 9, 11, 11, 12, 13, 14, 14, 15, 16, 16, 17, 17, 18, 19, 21, 21, 22, 23, 24, 25, 25, 26, 26, 29, 29, 29, 30, 30, 32, 33, 33, 33, 34, 34, 36, 36, 36, 37, 37, 38, 39, 39, 39, 41, 41, 41, 42, 42, 43, 44, 44, 44, 45, 45, 46, 46, 46, 46, 47, 47, 48, 48, 49, 49, 49
Offset: 1

Views

Author

Giovanni Teofilatto, Oct 07 2006

Keywords

Crossrefs

Cf. A104103 number of squares < prime(n).

Programs

  • Mathematica
    ltp=Select[Prime[Range[PrimePi[2500]]],PrimeQ[#+2]&];Ceiling[Sqrt[ltp]] (* James C. McMahon, Nov 17 2024 *)

Formula

a(n)=A003059(A001359(n)). - R. J. Mathar, Jun 18 2008

Extensions

More terms from R. J. Mathar, Jun 18 2008
Showing 1-6 of 6 results.