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 1-4 of 4 results.

A176583 n^2+Smallest cube, (Smallest cube >= n^2).

Original entry on oeis.org

0, 2, 12, 36, 43, 52, 100, 113, 128, 206, 225, 246, 360, 385, 412, 568, 599, 632, 667, 873, 912, 953, 996, 1258, 1305, 1354, 1405, 1458, 1784, 1841, 1900, 1961, 2355, 2420, 2487, 2556, 2627, 3097, 3172, 3249, 3328, 3409, 3961, 4046, 4133, 4222, 4313, 4953
Offset: 1

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Comments

4+8=12, 9+27=36, 16+27=43,..

Crossrefs

Programs

  • Mathematica
    r[n_]:=n^2;f[n_]:=r[n]+Ceiling[r[n]^(1/3)]^3;Table[f[n],{n,0,5!}]
    Table[n^2+Ceiling[Surd[n^2,3]]^3,{n,0,50}] (* Harvey P. Dale, Jun 04 2016 *)

A176584 Primes of the form p = k^3 + (largest square <= k^3).

Original entry on oeis.org

2, 194057, 601067, 1607173, 3283993, 3630257, 3721363, 4918999, 5255713, 5848307, 6749569, 9999907, 17992913, 20432729, 23393483, 34746203, 44845993, 73843813, 84277273, 107165033, 109735649, 120469409, 125138873, 130898927
Offset: 1

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Consider k = 4 * x^2 + 1, where the largest square <= k^3 is (8 * x^3 + 3 * x)^2. Bunyakowsky's conjecture implies there are infinitely many primes of the form (4 * x^2 + 1)^3 + (8 * x^3 + 3 * x)^2, and so that the sequence is infinite. The first term of this form is 93389778901 = a(165), corresponding to x = 30. - Robert Israel, Jan 10 2024

Crossrefs

Programs

  • Maple
    g:= n -> n + floor(sqrt(n))^2:
    select(isprime,map(g,[seq(i^3,i=1..1000)])); # Robert Israel, Jan 10 2024
  • Mathematica
    r[n_]:=n^3;f[n_]:=r[n]+Floor[Sqrt[r[n]]]^2;Select[Table[f[n],{n,0,6!}],PrimeQ[ # ]&]
  • PARI
    select(isprime, vector(1000, n, n^3+sqrtint(n^3)^2)) \\ Michel Marcus, Jan 10 2024

A176585 Primes of the form n^3+Smallest square, (Smallest square >= n^3).

Original entry on oeis.org

2, 17, 269, 281233, 1770217, 1826609, 2520841, 3907529, 7595017, 8665471, 9828089, 11280377, 12259063, 17235221, 27654961, 54008809, 70583033, 75196799, 85018949, 87240233, 106316057, 111499057, 168061561, 176255669, 201105409
Offset: 1

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8+9=17, 5^3+12^2=269,..

Crossrefs

Programs

  • Mathematica
    r[n_]:=n^3;f[n_]:=r[n]+Ceiling[Sqrt[r[n]]]^2;Select[Table[f[n],{n,0,6!}],PrimeQ[ # ]&]
    ssn3[n_]:=n^3+(Ceiling[Sqrt[n^3]])^2; Select[Array[ssn3,500],PrimeQ] (* Harvey P. Dale, Jun 23 2017 *)

A176586 Primes of the form : n^3 + Largest square + Smallest square, (Largest square <= n^3, Smallest square >= n^3).

Original entry on oeis.org

3, 222601, 2824933, 3573761, 4215749, 5183821, 6001997, 6592613, 7886597, 8592401, 9725393, 10127813, 10531813, 12751093, 13720661, 15263009, 18087529, 30232597, 52730113, 68727469, 79395353, 109787269, 139967461, 162040453
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    r[n_]:=n^3;f[n_]:=r[n]+Floor[Sqrt[r[n]]]^2+Ceiling[Sqrt[r[n]]]^2;Select[Table[f[n],{n,0,7!}],PrimeQ[ # ]&]
    lsss[n_]:=Module[{c=n^3},c+Floor[Sqrt[c]]^2+Ceiling[Sqrt[c]]^2]; Select[Array[ lsss,1000],PrimeQ] (* Harvey P. Dale, Feb 22 2023 *)
  • PARI
    print1(3);for(n=2,1e3,t=sqrtint(n^3);if(isprime(t=n^3+t^2+ (t+1)^2) && !issquare(n),print1(", "t))) \\ Charles R Greathouse IV, Apr 15 2012
Showing 1-4 of 4 results.