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 1-4 of 4 results.

A302354 Expansion of (Sum_{i>=1} x^prime(i))*(Sum_{j>=0} x^(j^3)).

Original entry on oeis.org

0, 1, 2, 1, 1, 1, 1, 1, 0, 1, 2, 1, 2, 1, 1, 0, 1, 1, 2, 1, 1, 0, 1, 1, 1, 0, 1, 0, 2, 2, 2, 2, 0, 1, 0, 0, 2, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 2, 1, 0, 1, 0, 1, 3, 2, 2, 1, 2, 1, 1, 2, 2, 0, 1, 0, 2, 2, 2, 0, 2, 1, 0, 1, 2, 1, 1, 1, 1, 0, 1, 1, 1, 0, 2, 2, 0, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 2, 2, 0, 1, 1, 1, 1, 2
Offset: 1

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Author

Ilya Gutkovskiy, Apr 06 2018

Keywords

Comments

Number of representations of n as the sum of a prime number and a nonnegative cube.

Examples

			a(11) = 2 because 11 = 3 + 2^3 = 11 + 0^3.
		

Crossrefs

Programs

  • Mathematica
    nmax = 120; Rest[CoefficientList[Series[Sum[x^Prime[i], {i, 1, nmax}] Sum[x^j^3, {j, 0, nmax}], {x, 0, nmax}], x]]

Formula

G.f.: (Sum_{i>=1} x^prime(i))*(Sum_{j>=0} x^(j^3)).

A365167 Number of representations of n as the sum of a prime number and a fourth power of a positive integer.

Original entry on oeis.org

0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 2, 1, 1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 2, 2, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 2, 1, 1, 0, 1, 0, 2, 1, 0, 0, 1, 0, 2, 0, 1, 1, 1, 0, 0, 1, 1, 1
Offset: 1

Views

Author

Ilya Gutkovskiy, Aug 24 2023

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 120; CoefficientList[Series[Sum[x^Prime[i], {i, 1, nmax}] Sum[x^j^4, {j, 1, nmax^(1/4)}], {x, 0, nmax}], x] // Rest

Formula

G.f.: (Sum_{i>=1} x^prime(i)) * (Sum_{j>=1} x^(j^4)).

A365290 a(n) is the least positive integer that can be expressed as the sum of a prime number and a positive cube in exactly n ways.

Original entry on oeis.org

1, 3, 30, 128, 1130, 2214, 6654, 10358, 24496, 37599, 64034, 59455, 85377, 158435, 240074, 253628, 313407, 405925, 548802, 891845, 809384, 1317788, 1547004, 2049122, 1838349, 2516848, 3192927, 2448059, 4349417, 4709007, 4438311, 6483753, 6175237, 8306209
Offset: 0

Views

Author

Ilya Gutkovskiy, Aug 31 2023

Keywords

Examples

			For n = 3: 128 = 3 + 5^3 = 101 + 3^3 = 127 + 1^3.
		

Crossrefs

Extensions

More terms from Rémy Sigrist, Sep 07 2023

A307647 Numbers that are the sum of a prime number and a positive cube.

Original entry on oeis.org

3, 4, 6, 8, 10, 11, 12, 13, 14, 15, 18, 19, 20, 21, 24, 25, 27, 29, 30, 31, 32, 34, 37, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50, 51, 54, 55, 56, 58, 60, 61, 62, 64, 66, 67, 68, 69, 70, 71, 72, 74, 75, 77, 79, 80, 81, 83, 84, 86, 87, 88, 90, 91, 93, 94, 95, 97, 98, 100, 101, 102, 104, 105
Offset: 1

Views

Author

Ilya Gutkovskiy, Apr 19 2019

Keywords

Crossrefs

Programs

  • Maple
    N:= 200: # for terms <= N
    P:= select(isprime,[2,seq(i,i=3..N-1,2)]):
    C:= [seq(j^3,j=1..floor((N-2)^(1/3)))]:
    sort(convert(select(`<=`,{seq(seq(p+c,p=P),c=C)},N),list)); # Robert Israel, Apr 22 2019

Formula

Exponents in expansion of (Sum_{i>=1} x^prime(i)) * (Sum_{j>=1} x^(j^3)).
Showing 1-4 of 4 results.