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.

A018143 Powers of fifth root of 10 rounded up.

Original entry on oeis.org

1, 2, 3, 4, 7, 10, 16, 26, 40, 64, 100, 159, 252, 399, 631, 1000, 1585, 2512, 3982, 6310, 10000, 15849, 25119, 39811, 63096, 100000, 158490, 251189, 398108, 630958, 1000000, 1584894, 2511887, 3981072, 6309574
Offset: 0

Views

Author

N. J. A. Sloane

Keywords

Crossrefs

Cf. A018141, A018142.

Programs

  • Mathematica
    Ceiling[Surd[10,5]^Range[0,40]] (* Harvey P. Dale, Dec 30 2017 *)
  • PARI
    a(n) = sqrtnint(10^n-1, 5) + 1; \\ Michel Marcus, Jun 26 2024

A374025 a(n) is the largest digit sum of all n-digit fifth powers.

Original entry on oeis.org

1, 5, 9, 27, 27, 36, 45, 46, 52, 63, 72, 80, 89, 90, 99, 104, 108, 119, 126, 143, 137, 152, 157, 162, 175, 180, 182, 189, 198, 208, 209, 216, 225, 234, 236, 250, 253, 270, 270, 284, 286, 288, 297, 310, 315, 323, 324, 334, 341, 346, 351, 364
Offset: 1

Views

Author

Zhining Yang, Jun 25 2024

Keywords

Examples

			a(5) = 27 because 27 is the largest digital sum encountered among all 5-digit fifth powers (16807, 32768, 59049).

Crossrefs

Cf. A055566, A018141, A018143, A348300, A373727, A373914.

Programs

  • Mathematica
    Table[Max@Map[Total@IntegerDigits[#^5] &, Range[Ceiling[10^((n - 1)/5)], Floor[(10^n-1)^(1/5)]]], {n, 40}]
  • Python
    from sympy import integer_nthroot
def A374025(n): return max(sum(int(d) for d in str(m**5)) for m in range((lambda x:x[0]+(x[1]^1))(integer_nthroot(10**(n-1),5)),1+integer_nthroot(10**n-1,5)[0])) # Chai Wah Wu, Jun 26 2024

Extensions

a(41)-a(49) from Chai Wah Wu, Jun 26 2024
a(50)-a(52) from Chai Wah Wu, Jun 27 2024
Showing 1-2 of 2 results.

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

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