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.

A127601 Integer part of 4th root of product of first n primes.

Original entry on oeis.org

1, 1, 1, 2, 3, 6, 13, 26, 55, 122, 283, 669, 1650, 4176, 10694, 28002, 75555, 209402, 585212, 1674296, 4860120, 14206194, 42353033, 127836257, 392646335, 1232237672, 3906383039, 12444691408, 40024883480, 129326254765
Offset: 0

Views

Author

Artur Jasinski, Jan 19 2007

Keywords

Comments

For n>=6, a(n) >= prime(n+1).
a(n) gives the number of pairs within A002110(n) of the form {x, x^4} where x is nonzero positive integer. - Soumyadeep Dhar, May 16 2021

Links

Crossrefs

Cf. A002110, A060797, A127600, A127602, A127603, A127604.

Programs

  • Mathematica
    a = {}; Do[b = 1; Do[b = b Prime[x], {x, 1, n}]; AppendTo[a, Floor[b^(1/4)]], {n, 1, 50}]; a
  • PARI
    a(n)={sqrtnint(vecprod(primes(n)), 4)} \\ Andrew Howroyd, Apr 27 2021

Extensions

a(0)=1 prepended by Soumyadeep Dhar, Apr 28 2021

A127602 Integer part of 5th root of product of first n primes.

Original entry on oeis.org

1, 1, 1, 2, 4, 7, 13, 24, 46, 91, 182, 375, 788, 1672, 3612, 7991, 18062, 41100, 95294, 223520, 527208, 1263303, 3057195, 7502417, 18730768, 47143287, 119120718, 303294169, 775085050, 1995101748, 5256852524, 13937345067, 37284143091
Offset: 1

Views

Author

Artur Jasinski, Jan 19 2007

Keywords

Crossrefs

Cf. A002110, A060797, A127600, A127601, A127603, A127604.

Programs

  • Mathematica
    a = {}; Do[b = 1; Do[b = b Prime[x], {x, 1, n}]; AppendTo[a, Floor[b^(1/5)]], {n, 1, 50}]; a
Floor[Surd[#,5]]&/@FoldList[Times,Prime[Range[40]]] (* Harvey P. Dale, Nov 16 2017 *)

A127604 Integer part of 7th root of product of first n primes.

Original entry on oeis.org

1, 1, 1, 2, 3, 4, 6, 9, 15, 25, 41, 68, 117, 200, 347, 613, 1097, 1975, 3601, 6621, 12221, 22814, 42891, 81443, 156560, 302701, 586897, 1144127, 2236326, 4393717, 8777595, 17613387, 35570395, 71983616, 147125801, 301280666, 620399178, 1284393250
Offset: 1

Views

Author

Artur Jasinski, Jan 19 2007

Keywords

Crossrefs

Cf. A002110, A060797, A127600, A127601, A127602, A127603.

Programs

  • Mathematica
    a = {}; Do[b = 1; Do[b = b Prime[x], {x, 1, n}]; AppendTo[a, Floor[b^(1/7)]], {n, 1, 50}]; a

A056127 Minimum m where product_{k=1 to m}[p_k] > (p_{m+1})^n, where p_k is k-th prime.

Original entry on oeis.org

1, 2, 4, 5, 7, 8, 10, 11, 13, 14, 15, 16, 18, 19, 20, 21, 23, 24, 25, 26, 28, 29, 30, 32, 33, 34, 35, 36, 38, 39, 40, 41, 43, 44, 45, 46, 48, 49, 50, 51, 52, 53, 55, 56, 57, 58, 59, 60, 62, 63, 64, 65, 67, 68, 69, 70, 72, 73, 74, 75, 76, 78, 79, 80, 81, 82, 83, 85, 86, 87, 88
Offset: 0

Views

Author

Leroy Quet, Aug 30 2000

Keywords

Examples

			a(2) = 4, since 2*3*5 < 7^2, but 2*3*5*7 > 11^2. (The product of the first 4 primes is greater than the 5th prime squared.)

Links

Crossrefs

Cf. A002110, A060797, A127600, A127601, A127602, A127603, A127604.

Programs

  • Mathematica
    a = {}; Do[x = 1; While[Prime[x + 1] >= (Product[Prime[x], {x, 1, x}])^(1/n), x++ ]; AppendTo[a, x], {n, 1, 100}]; a (* Artur Jasinski, May 11 2007 *)
Showing 1-4 of 4 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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