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.

A365126 Number of representations of n as the sum of a prime number and a fourth power of a nonnegative integer.

Original entry on oeis.org

0, 1, 2, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 2, 2, 1, 1, 0, 2, 1, 0, 0, 1, 0, 2, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 2, 1, 0, 0, 0, 0, 2, 1, 0, 0, 1, 0, 2, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 3, 2, 0, 1, 1, 1, 2, 1, 0, 1, 0, 1, 1, 0, 1, 2, 1, 1, 1, 1, 1, 2, 1, 0, 1, 1, 1, 2, 0, 1, 2, 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, 0, nmax^(1/4)}], {x, 0, nmax}], x] // Rest

Formula

G.f.: (Sum_{i>=1} x^prime(i)) * (Sum_{j>=0} x^(j^4)).

A365168 Numbers that are the sum of a prime number and a fourth power of a positive integer.

Original entry on oeis.org

3, 4, 6, 8, 12, 14, 18, 19, 20, 21, 23, 24, 27, 29, 30, 32, 33, 35, 38, 39, 42, 44, 45, 47, 48, 53, 54, 57, 59, 60, 62, 63, 68, 69, 72, 74, 75, 77, 80, 83, 84, 86, 87, 88, 89, 90, 92, 94, 95, 98, 99, 100, 102, 104, 105, 108, 110, 112, 113, 114, 117, 118, 119, 122, 123, 124, 125
Offset: 1

Views

Author

Ilya Gutkovskiy, Aug 24 2023

Keywords

Crossrefs

Programs

  • Maple
    N:= 200: # for terms up to N
    P:= select(isprime,{$2..N-1}):
    F:= {seq(i^4,i=1..floor(N^(1/4)))}:
    sort(convert({seq(seq(s+t,s=P),t=F)},list)); # Robert Israel, Aug 28 2024
  • Mathematica
    nmax = 125; f[x_] := Sum[x^Prime[i], {i, 1, nmax}] Sum[x^j^4, {j, 1, nmax^(1/4)}]; Exponent[#, x] & /@ List @@ Normal[Series[f[x], {x, 0, nmax}]]

A365169 Numbers that are not the sum of a prime number and a fourth power of a positive integer.

Original entry on oeis.org

1, 2, 5, 7, 9, 10, 11, 13, 15, 16, 17, 22, 25, 26, 28, 31, 34, 36, 37, 40, 41, 43, 46, 49, 50, 51, 52, 55, 56, 58, 61, 64, 65, 66, 67, 70, 71, 73, 76, 78, 79, 81, 82, 85, 91, 93, 96, 97, 101, 103, 106, 107, 109, 111, 115, 116, 120, 121, 126, 127, 130, 131, 133, 135
Offset: 1

Views

Author

Ilya Gutkovskiy, Aug 24 2023

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 138; Position[CoefficientList[Series[Sum[x^Prime[i], {i, 1, nmax}] Sum[x^j^4, {j, 1, nmax^(1/4)}], {x, 0, nmax}], x] // Rest, 0] // Flatten

A365292 a(n) is the least positive integer that can be expressed as the sum of a prime number and a fourth power of a positive integer in exactly n ways.

Original entry on oeis.org

1, 3, 18, 644, 1298, 6662, 14948, 29102, 77579, 102044, 181838, 367022, 545828, 754652, 1095254, 1985807, 1875902, 2672339, 4102958, 4851593, 7444799, 6826874, 10715858, 16398674, 18805058, 23502134, 31500614, 34967159, 41824499, 47158793, 54659384, 67269347, 83885588
Offset: 0

Views

Author

Ilya Gutkovskiy, Aug 31 2023

Keywords

Examples

			For n = 3: 644 = 19 + 5^4 = 563 + 3^4 = 643 + 1^4.
		

Crossrefs

Extensions

More terms from Jinyuan Wang, Sep 13 2023
Showing 1-4 of 4 results.