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 1-3 of 3 results.

A090845 Let A denote the sequence; A is equal to the union of the self-convolutions A^2 and A^3, with terms in ascending order by size.

Original entry on oeis.org

1, 1, 2, 3, 5, 9, 10, 20, 22, 40, 51, 67, 114, 126, 203, 230, 354, 468, 571, 885, 908, 1486, 1674, 2250, 3045, 3586, 5322, 5418, 8186, 9560, 12234, 16341, 17976, 26970, 27912, 38435, 46383, 57024, 76794, 80805, 116376, 125205, 165914, 201580, 232352
Offset: 0

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Author

Paul D. Hanna, Dec 09 2003

Keywords

Comments

The occurrences of the terms of A^3 in A is given by A090846.
The self-convolution square equals A222082.
The self-convolution cube equals A222083.
Not equal to A262990.

Examples

			A={1,1,2,3,5,9,10,20,22,40,51,...} since A is the sorted union of:
A^2={1,2,5,10,20,40,67,126,203,354,571,908,1486,2250,3586,...} and
A^3={1,3,9,22,51,114,230,468,885,1674,3045,5418,9560,16341,...}.
		

Crossrefs

Cf. A090846, A222082 (A^2), A222083 (A^3).

Programs

  • PARI
    {a(n)=local(A=[1,1]);for(i=1,#binary(3*n+1),A=vecsort(concat(Vec(Ser(A)^2),Vec(Ser(A)^3))));A[n+1]}
    for(n=0,60,print1(a(n),", "))

A222082 Self-convolution square of A090845.

Original entry on oeis.org

1, 2, 5, 10, 20, 40, 67, 126, 203, 354, 571, 908, 1486, 2250, 3586, 5322, 8186, 12234, 17976, 26970, 38435, 57024, 80805, 116376, 165914, 232352, 332196, 456154, 645469, 885826, 1225998, 1692686, 2290512, 3168986, 4242896, 5805526, 7782803, 10459912, 14110205
Offset: 0

Views

Author

Paul D. Hanna, Feb 06 2013

Keywords

Examples

			G.f.: A(x) = 1 + 2*x + 5*x^2 + 10*x^3 + 20*x^4 + 40*x^5 + 67*x^6 +...
Let G(x) = A(x)^(1/2) denote the g.f. of A090845:
G(x) = 1 + x + 2*x^2 + 3*x^3 + 5*x^4 + 9*x^5 + 10*x^6 + 20*x^7 + 22*x^8 + 40*x^9 + 51*x^10 + 67*x^11 + 114*x^12 + 126*x^13 + 203*x^14 +...
then the coefficients of G(x)^2 and G(x)^3 begin:
G(x)^2: [1, 2, 5, 10, 20, 40, 67, 126, 203, 354, 571, 908, 1486, ...];
G(x)^3: [1, 3, 9, 22, 51, 114, 230, 468, 885, 1674, 3045, 5418, ..];
where the sorted union of these coefficients yield sequence A090845.
		

Crossrefs

Programs

  • PARI
    {a(n)=local(A=[1, 1]); for(i=1, #binary(3*n+1), A=vecsort(concat(Vec(Ser(A)^2), Vec(Ser(A)^3)))); Vec(Ser(A)^2)[n+1]}
    for(n=0, 60, print1(a(n), ", "))

A090846 Positions of the terms of A090845^3 in A090845, where A090845 is equal to the union of the self-convolutions A090845^2 and A090845^3, in ascending order by size, starting with A090845(0)=1.

Original entry on oeis.org

1, 3, 5, 8, 10, 12, 15, 17, 19, 22, 24, 27, 29, 31, 34, 36, 38, 41, 43, 45, 48, 50, 53, 55, 57, 60, 62, 64, 67, 69, 72, 74, 76, 79, 81, 83, 86, 88, 90, 93, 95, 98, 100, 102, 105, 107, 109, 112, 114, 117, 119, 121, 124, 126, 128, 131, 133, 135, 138, 140, 143, 145, 147, 150
Offset: 0

Views

Author

Paul D. Hanna, Dec 09 2003

Keywords

Comments

What is the value of limit a(n)/n ? Example: a(12000)/12000 = 2.3758333...

Examples

			a(4)=10 since A090845^3(4)=A090845(10)=51, where
A090845={1,1,2,3,5,9,10,20,22,40,51,...} and
A090845^3={1,3,9,22,51,114,230,468,885,1674,3045,5418,...}.
		

Crossrefs

Formula

A090845(a(n)) = A222083(n) for n>=0, where A222083 is the self-convolution cube of A090845.
Showing 1-3 of 3 results.