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 1-5 of 5 results.

A121571 Largest number that is not the sum of n-th powers of distinct primes.

Original entry on oeis.org

6, 17163, 1866000
Offset: 1

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Author

T. D. Noe, Aug 08 2006

Keywords

Comments

As stated by Sierpinski, H. E. Richert proved a(1) = 6. Dressler et al. prove a(2) = 17163.
Fuller & Nichols prove T. D. Noe's conjecture that a(3) = 1866000. They also prove that 483370 positive numbers cannot be written as the sum of cubes of distinct primes. - Robert Nichols, Sep 08 2017
Noe conjectures that a(4) = 340250525752 and that 31332338304 positive numbers cannot be written as the sum of fourth powers of distinct primes. - Charles R Greathouse IV, Nov 04 2017

Examples

			a(1) = 6 because only the numbers 1, 4 and 6 are not the sum of distinct primes.
		

References

  • W. Sierpinski, Elementary Theory of Numbers, Warsaw, 1964, p. 143-144.

Crossrefs

Cf. A231407 (numbers that are not the sum of distinct primes).
Cf. A121518 (numbers that are not the sum of squares of distinct primes).
Cf. A213519 (numbers that are the sum of cubes of distinct primes).
Cf. A001661 (integers instead of primes).

Formula

a(1) = A231407(3), a(2) = A121518(2438). - Jonathan Sondow, Nov 26 2013

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

A234320 Largest number that is not the sum of distinct primes of the form 2k+1, 4k+1, 4k+3, 6k+1, 6k+5, ...; or 0 if none exists.

Original entry on oeis.org

9, 121, 55, 205, 161
Offset: 1

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Author

Jonathan Sondow, Dec 28 2013

Keywords

Comments

Largest number that is not the sum of distinct primes of the form 2nk+r for fixed n > 0 and 0 < r < 2n with gcd(2n,r) = 1.
n = 1: Dressler proved that 9 is the largest integer which is not the sum of distinct odd primes.
n = 2 and 3: Makowski proved that the largest integer that is not the sum of distinct primes of the form 4k+1, 4k+3, 6k+1, 6k+5 is 121, 55, 205, 161, respectively.
n = 6: Dressler, Makowski, and Parker proved that the largest integer that is not the sum of distinct primes of the form 12k+1, 12k+5, 12k+7, 12k+11 is 1969, 1349, 1387, 1475.
For n = 4, 5, 7, 8, 9, ..., the largest number that is not the sum of distinct primes of the form 2nk+r seems to be unknown.

Examples

			The positive integers that are not the sum of distinct odd primes are A231408 = 1, 2, 4, 6, 9, so a(1) = A231408(5) = 9.
		

References

  • A. Makowski, Partitions into unequal primes, Bull. Acad. Polon. Sci. Sér. Math. Astronom. Phys., 8 (1960), 125-126.

Crossrefs

A234321 Positive integers that are not the sum of distinct Ramanujan primes.

Original entry on oeis.org

1, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 23, 24, 25, 26, 27, 32, 33, 34, 35, 36, 37, 38, 39, 44, 45, 50, 51, 53, 55, 56, 62, 63, 65, 68, 74, 79, 85, 91, 92, 94, 122
Offset: 1

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Author

Jonathan Sondow, Dec 28 2013

Keywords

Comments

Paksoy showed that every integer > 122 is the sum of distinct Ramanujan primes (A104272).

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 1-5 of 5 results.