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.

A110630 Every 2nd term of A083954 such that the self-convolution 2nd power is congruent modulo 8 to A083954, which consists entirely of numbers 1 through 4.

Original entry on oeis.org

1, 2, 3, 4, 1, 4, 3, 4, 3, 4, 2, 2, 4, 4, 3, 2, 2, 2, 3, 2, 3, 2, 4, 2, 2, 4, 2, 4, 2, 2, 1, 4, 1, 2, 4, 4, 1, 2, 3, 4, 4, 4, 3, 4, 2, 2, 2, 2, 1, 4, 1, 2, 3, 2, 4, 4, 1, 4, 1, 4, 2, 2, 3, 4, 2, 4, 2, 4, 3, 4, 4, 2, 4, 2, 1, 2, 4, 4, 4, 4, 1, 2, 4, 4, 2, 2, 3, 4, 1, 2, 2, 4, 1, 2, 4, 4, 3, 2, 3, 4, 1, 4, 4, 4, 3
Offset: 0

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Examples

			A(x) = 1 + 2*x + 3*x^2 + 4*x^3 + x^4 + 4*x^5 + 3*x^6 + 4*x^7 +...
A(x)^2 = 1 + 4*x + 10*x^2 + 20*x^3 + 27*x^4 + 36*x^5 + 44*x^6 +...
A(x)^2 (mod 8) = 1 + 4*x + 2*x^2 + 4*x^3 + 3*x^4 + 4*x^5 +...
G083954(x) = 1 + 4*x + 2*x^2 + 4*x^3 + 3*x^4 + 4*x^5 + 4*x^6 +...
where G083954(x) is the g.f. of A083954.
		

Crossrefs

Programs

  • PARI
    {a(n)=local(d=2,m=4,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)}

Formula

a(n) = A083954(2*n) for n>=0.