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.

Previous Showing 21-22 of 22 results.

A194566 Centered cube numbers: (n+1)^100+n^100.

Original entry on oeis.org

1, 1267650600228229401496703205377, 515377520732011332304111729993850674198810727377, 1606938044259505653062694103672199063651968615055494942823377
Offset: 0

Views

Author

Jonathan Vos Post, Aug 29 2011

Keywords

Comments

Can never be prime, and after a(0) must have at least 3 prime factors, as a(n) = (2*n^4 + 4*n^3 + 6*n^2 + 4*n + 1) * p_16(n) * p_80(n).

Crossrefs

Programs

  • Maple
    a:= n-> (n+1)^100 +n^100: seq (a(n), n=0..20);
  • Mathematica
    Total/@Partition[Range[0,5]^100,2,1] (* Harvey P. Dale, Aug 10 2013 *)

Formula

a(n) = (n+1)^100 + n^100.

A244947 Least number k > n such that k^16 + n^16 is prime.

Original entry on oeis.org

2, 85, 4, 33, 6, 7, 8, 13, 22, 13, 16, 41, 28, 15, 22, 19, 24, 23, 54, 31, 22, 27, 56, 61, 38, 29, 40, 37, 34, 61, 32, 35, 82, 35, 46, 43, 40, 49, 58, 67, 42, 55, 58, 49, 46, 61, 58, 61, 68, 73, 92, 63, 94, 77, 166, 57, 82, 63, 72, 109, 76, 121, 82, 79, 86, 67, 72, 77, 82, 71, 98
Offset: 1

Views

Author

Derek Orr, Jul 08 2014

Keywords

Comments

a(n) = n+1 iff n is in A154535.

Examples

			10^16 + 11^16 = 55949729863572161 is not prime. 10^16 + 12^16 = 2^16*(5^16+6^16) is not prime. 10^16 + 13^16 = 675416609183179841 is prime. Thus a(10) = 13.
		

Crossrefs

Programs

  • PARI
    a(n)=for(k=n+1,10^4,if(isprime(k^16+n^16),return(k)))
    n=1;while(n<100,print1(a(n),", ");n++)
  • Python
    import sympy
    from sympy import isprime
    def a(n):
      for k in range(n+1,10**4):
        if isprime(k**16+n**16):
          return k
    n = 1
    while n < 100:
      print(a(n),end=', ')
      n += 1
    
Previous Showing 21-22 of 22 results.