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.

A360478 Least k such that the first n primes divide k and the next n primes divide k+1.

Original entry on oeis.org

2, 174, 11010, 877590, 3576536040, 7300395162060, 8122095802580760, 15497422946114018910, 6949903578918639188850, 482875127106370562524140180, 2448313281623289989477792853630, 20024982066721727911275778517919720, 29200503600421680216708710172770859570
Offset: 1

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Author

Samuel Harkness, Feb 08 2023

Keywords

Examples

			a(3) = 11010 because the first 3 primes {2, 3, 5} divide 11010 and the next 3 primes {7, 11, 13} divide 11011.
		

Crossrefs

Cf. A069561.

Programs

  • Mathematica
    K = {}; For[n = 1, n <= 13, n++, R = Prime[Range[2 n]];
     A = R[[1 ;; n]]; t = Times @@ A; B = R[[n + 1 ;; 2 n]]; p = t + 1;
     For[b = 1, b <= n, b++, While[Mod[p, Part[B, b]] != 0, p += t];
      t *= Part[B, b]]; AppendTo[K, p - 1]]; Print[K]
  • PARI
    a(n)={my(p=primes(2*n)); lift(chinese(Mod(0, vecprod(p[1..n])), Mod(-1, vecprod(p[n+1..2*n]))))} \\ Andrew Howroyd, Feb 08 2023