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 1-2 of 2 results.

A362954 Numbers k such that k + the sum of the fourth powers of its digits is again a fourth power.

Original entry on oeis.org

0, 6047, 7518, 8127, 12207, 25247, 50000, 71966, 77326, 89582, 156156, 376189, 384624, 384640, 599611, 611356, 700158, 794139, 796715, 800558, 1172829, 1329051, 1329324, 1329340, 1488080, 1492525, 1862190, 2546894, 2547885, 5295852, 5302286, 5755548, 6244080, 6246510, 7291980, 7869294
Offset: 0

Views

Author

Will Gosnell and M. F. Hasler, May 09 2023

Keywords

Crossrefs

Cf. A000583 (4th powers), A055013 (sum of 4th powers of decimal digits of n).
Cf. A362953 (the same for 3rd powers).

Programs

  • PARI
    select( {is(n,p=4)=ispower(vecsum([d^p|d<-digits(n)])+n,p)}, [0..10^5])
    
  • Python
    aupto   = 7869300
    A362954 = []
    A000583 = set(fp**4 for fp in range(0, int(aupto**(1/4)+3)))
    for n in range(0, aupto+1):
        if n + sum(int(digit)**4 for digit in str(n)) in A000583: A362954.append(n)
    print(A362954) # Karl-Heinz Hofmann, Jun 02 2023

A362945 Numbers k such that k + the sum of the fifth powers of its digits is again a fifth power.

Original entry on oeis.org

0, 210, 66374, 76933, 294137, 722571, 741300, 1023716, 2412593, 3959235, 4022940, 5090402, 6351886, 7821198, 9653864, 11808061, 11814811, 20427955, 24190287, 24239133, 24245187, 33518020, 33532714, 33536551, 39060306, 52476271, 52480534, 69255266, 69265142, 79091461, 89980491, 90147222
Offset: 0

Views

Author

M. F. Hasler, Jun 15 2023

Keywords

Crossrefs

Cf. A000584 (4th powers), A055014 (sum of 5th powers of decimal digits).
Cf. A362953 (same for 3rd powers), A362954 (same for 4th powers).

Programs

  • PARI
    is_A362945(n,p=5)=ispower(vecsum([d^p|d<-digits(n)])+n,p)
    for(n=0,1e8, is_A362945(n) && print1(n", "))
    
  • Python
    ispower5 = lambda n: n==round(n**.2)**5
    is_A362945 = lambda n: ispower5(sum(int(d)**5 for d in str(n))+n)
    def A362945(n, A=[0]):
        while len(A) < n:
            A.append(A[-1]+1)
            while not is_A362945(A[-1]): A[-1]+=1
        return A[n]
Showing 1-2 of 2 results.