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 1-3 of 3 results.

A125907 Numbers k such that k divides 2^4 + 3^4 + 5^4 + ... + prime(k)^4.

Original entry on oeis.org

1, 2951, 38266951, 3053263643573, 3798632877308897
Offset: 1

Views

Author

Alexander Adamchuk, Feb 04 2007

Keywords

Comments

No more terms to 10^13. - Charles R Greathouse IV, Mar 21 2011
a(4) is less than 10^13 contradicting the previous comment. It was found using the primesieve library by Kim Walisch and gmplib. - Bruce Garner, Feb 26 2021
a(6) > 4*10^15. - Paul W. Dyson, Nov 19 2024

Crossrefs

Cf. A085450 = smallest m > 1 such that m divides Sum_{k=1..m} prime(k)^n.

Programs

  • Mathematica
    a(1) = 1; s = 2^4; Do[s = s + Prime[2n]^4+Prime[2n+1]^4; If[ Mod[s, 2n+1] == 0, Print[2n+1]], {n,1, 20000000}]
  • PARI
    s=0; n=0; forprime(p=2, 4e9, s+=p^4; if(s%n++==0, print1(n", "))) \\ Charles R Greathouse IV, Mar 21 2011

Extensions

a(4) from Bruce Garner, Feb 26 2021
a(5) from Paul W. Dyson, May 09 2024

A341689 a(n) is the sum of the 4th power of the first A125907(n) primes.

Original entry on oeis.org

16, 282090779141153551270, 2210712955689035458600206881540015387708550, 48675866046797839528447895106845001955284425583991669795082795118772, 340116502128393540096171523813533871084766138971398067752157768889198596930173282496
Offset: 1

Views

Author

Karl-Heinz Hofmann, Feb 17 2021

Keywords

Crossrefs

Programs

  • Python
    sum = 0
    for n in range(1,10000000000001):
        sum += pow(prime[n],4)
        if sum % n == 0:
            print(n, prime[n], sum, (sum // n))

Extensions

a(4) from Martin Ehrenstein, Feb 27 2021
a(5) from Paul W. Dyson, May 09 2024

A341690 Integer averages of first n primes to the 4th power for some n (A341689(n)/A125907(n)).

Original entry on oeis.org

16, 95591589000729770, 57770815231373815452404527382911050, 15942241394469365582203327807497328235663420076612273764, 89536555153849358635668155008982165719026544119306300984594045157568
Offset: 1

Views

Author

Karl-Heinz Hofmann, Feb 17 2021

Keywords

Crossrefs

Programs

  • Python
    sum = 0
    for n in range(1, 10000000000001):
        sum += pow(prime[n], 4)
        if sum % n == 0:
            print(n, prime[n], sum, (sum // n))

Extensions

a(4) from Martin Ehrenstein, Feb 27 2021
a(5) from Paul W. Dyson, May 09 2024
Showing 1-3 of 3 results.