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 1-7 of 7 results.

A001661 Largest number not the sum of distinct positive n-th powers.

Original entry on oeis.org

128, 12758, 5134240, 67898771, 11146309947, 766834015734, 4968618780985762
Offset: 2

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Author

Keywords

Comments

a(8) > 74^8. - Donovan Johnson, Nov 23 2010
Fuller and Nichols prove that a(6) = 11146309947 and that 2037573096 positive numbers cannot be written as the sum of distinct 6th powers. - Robert Nichols, Sep 09 2017
a(8) >= 83^8 ~ 2.25e15 since A030052(8) = 84. Similarly, a(9..15) >= (46^9, 62^10, 67^11, 80^12, 101^13, 94^14, 103^15) ~ (9.2e14, 8.4e17, 1.2e20, 6.9e22, 1.1e26, 4.2e27, 1.6e30), cf. formula. Most often a(n) will be closer to and even larger than A030052(n)^n. - In the literature, a(n)+1 is known as the anti-Waring number N(n,1). - M. F. Hasler, May 15 2020
a(9..16) > (1.55e17, 1.31e19, 1.64e21, 5.55e23, 1.32e26, 1.37e28, 2.09e30, 9.99e35). - Michael J. Wiener, Jun 10 2023

References

  • S. Lin, Computer experiments on sequences which form integral bases, pp. 365-370 of J. Leech, editor, Computational Problems in Abstract Algebra. Pergamon, Oxford, 1970.
  • Harry L. Nelson, The Partition Problem, J. Rec. Math., 20 (1988), 315-316.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A121571 (primes instead of integers).

Formula

a(n) < d*2^(n-1)*(c*2^n + (2/3)*d*(4^n - 1) + 2*d - 2)^n + c*d, where c = n!*2^(n^2) and d = 2^(n^2 + 2*n)*c^(n-1) - 1, according to Kim [2016-2017]. - Danny Rorabaugh, Oct 11 2016
a(n) >= (A030052(n)-1)^n. - M. F. Hasler, May 15 2020

Extensions

a(7) from Donovan Johnson, Nov 23 2010
a(8) from Michael J. Wiener, Jun 10 2023

A231407 Positive integers that are not the sum of distinct primes.

Original entry on oeis.org

1, 4, 6
Offset: 1

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Author

Jonathan Sondow, Nov 24 2013

Keywords

Comments

Using elementary methods, Richert proved that 6 is the largest integer which is not the sum of distinct primes.

References

  • H.-E. Richert, Über Zerlegungen in paarweise verschiedene Zahlen, Norsk. Mat. Tidsskr., 31 (1949), 120-122.

Crossrefs

Formula

a(3) = A121571(1).

A213519 Numbers that are the sum of cubes of distinct primes.

Original entry on oeis.org

0, 8, 27, 35, 125, 133, 152, 160, 343, 351, 370, 378, 468, 476, 495, 503, 1331, 1339, 1358, 1366, 1456, 1464, 1483, 1491, 1674, 1682, 1701, 1709, 1799, 1807, 1826, 1834, 2197, 2205, 2224, 2232, 2322, 2330, 2349, 2357, 2540, 2548, 2567, 2575, 2665, 2673, 2692
Offset: 1

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Author

T. D. Noe, Jul 10 2012

Keywords

Comments

The complement of this sequence is conjectured to have 483370 terms, the last one being 1866000 = A121571(3).
This conjecture was proved by Fuller and Nichols (see the link). - Robert Nichols, Sep 17 2017

Crossrefs

Cf. A121571.

Programs

  • Mathematica
    lim = PrimePi[17]; s = {0}; Do[p = Prime[n]; s = Union[s, s + p^3], {n, lim}]; Select[s, # <= Prime[lim]^3 &]

A231408 Positive integers that are not the sum of distinct odd primes.

Original entry on oeis.org

1, 2, 4, 6, 9
Offset: 1

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Author

Jonathan Sondow, Nov 24 2013

Keywords

Comments

Using elementary methods, Dressler proved that 9 is the largest integer which is not the sum of distinct odd primes.

Crossrefs

A351326 a(n) is the least number k such that k and all larger numbers can be expressed as the sum of n-th powers of distinct primes.

Original entry on oeis.org

7, 17164, 1866001
Offset: 1

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Author

Ilya Gutkovskiy, Mar 24 2022

Keywords

Crossrefs

Formula

a(n) = A121571(n) + 1.

A352586 a(n) is the largest prime that is not the sum of n-th powers of distinct primes.

Original entry on oeis.org

12601, 1656517
Offset: 2

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Author

Ilya Gutkovskiy, Mar 21 2022

Keywords

Comments

The corresponding indices of primes are 1505, 125100.

Crossrefs

A352600 Number of positive integers that are not the sum of n-th powers of distinct primes.

Original entry on oeis.org

3, 2438, 483370
Offset: 1

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Author

Ilya Gutkovskiy, Mar 22 2022

Keywords

Crossrefs

Showing 1-7 of 7 results.