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.

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A112572 G.f. A(x) satisfies: A(x)^4 equals the g.f. of A110638, which consists entirely of numbers 1 through 8.

Original entry on oeis.org

1, 1, -1, 3, -6, 18, -52, 156, -481, 1512, -4828, 15621, -51081, 168537, -560309, 1874975, -6309964, 21341241, -72497698, 247247463, -846187023, 2905210526, -10003144986, 34532780087, -119499263663, 414431066955, -1440182574644, 5014115406096
Offset: 0

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Author

Paul D. Hanna, Sep 14 2005

Keywords

Comments

A110638 is formed from every 2nd term of A083948, which also consists entirely of numbers 1 through 8.

Examples

			A(x) = 1 + x - x^2 + 3*x^3 - 6*x^4 + 18*x^5 - 52*x^6 + 156*x^7 +...
A(x)^4 = 1 + 4*x + 2*x^2 + 4*x^3 + 7*x^4 + 8*x^5 + 4*x^6 +...
A(x)^8 = 1 + 8*x + 20*x^2 + 24*x^3 + 50*x^4 + 88*x^5 + 116*x^6 +...
A(x)^8 (mod 16) = 1 + 8*x + 4*x^2 + 8*x^3 + 2*x^4 + 8*x^5 +...
G(x) = 1 + 8*x + 4*x^2 + 8*x^3 + 2*x^4 + 8*x^5 + 4*x^6 + 8*x^7 +...
where G(x) is the g.f. of A083948.
		

Crossrefs

Programs

  • PARI
    {a(n)=local(d=2,m=8,A=1+m*x); for(j=2,d*n, for(k=1,m,t=polcoeff((A+k*x^j+x*O(x^j))^(1/m),j); if(denominator(t)==1,A=A+k*x^j;break))); polcoeff(Ser(vector(n+1,i,polcoeff(A,d*(i-1))))^(1/4),n)}

Formula

G.f. A(x) satisfies: A(x)^8 (mod 16) = g.f. of A083948.

A110637 Every 4th term of A083948 where the self-convolution 4th power is congruent modulo 16 to A083948, which consists entirely of numbers 1 through 8.

Original entry on oeis.org

1, 2, 7, 4, 3, 2, 1, 8, 6, 6, 6, 4, 4, 2, 8, 8, 7, 6, 8, 6, 8, 6, 7, 8, 3, 4, 3, 6, 3, 8, 1, 4, 4, 8, 3, 6, 6, 2, 5, 8, 1, 4, 6, 4, 6, 6, 1, 8, 1, 6, 5, 8, 4, 4, 8, 4, 5, 8, 5, 2, 4, 8, 6, 4, 5, 2, 8, 8, 7, 4, 6, 4, 5, 8, 6, 8, 6, 4, 5, 4, 8, 4, 4, 4, 7, 8, 4, 2, 1, 8, 3, 4, 7, 2, 7, 8, 4, 6, 6, 4, 8, 6, 7, 6, 4
Offset: 0

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Author

Keywords

Examples

			A(x) = 1 + 2*x + 7*x^2 + 4*x^3 + 3*x^4 + 2*x^5 + x^6 +...
A(x)^4 = 1 + 8*x + 52*x^2 + 216*x^3 + 754*x^4 + 2008*x^5 +...
A(x)^4 (mod 16) = 1 + 8*x + 4*x^2 + 8*x^3 + 2*x^4 + 8*x^5 +...
G(x) = 1 + 8*x + 4*x^2 + 8*x^3 + 2*x^4 + 8*x^5 + 4*x^6 +...
where G(x) is the g.f. of A083948.
		

Crossrefs

Programs

  • PARI
    {a(n)=local(d=4,m=8,A=1+m*x); for(j=2,d*n, for(k=1,m,t=polcoeff((A+k*x^j+x*O(x^j))^(1/m),j); if(denominator(t)==1,A=A+k*x^j;break)));polcoeff(A,d*n)}
Showing 1-2 of 2 results.