login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A106407 Expansion of x((1-x)(1-x^2)(1-x^4)(1-x^8)...)^2. 1
1, -2, -1, 4, -3, 2, 3, -8, 1, 6, -1, -4, 5, -6, -5, 16, -7, -2, 7, -12, 5, 2, -5, 8, 1, -10, -1, 12, -11, 10, 11, -32, 9, 14, -9, 4, 5, -14, -5, 24, -7, -10, 7, -4, -3, 10, 3, -16, 9, -2, -9, 20, -11, 2, 11, -24, 1, 22, -1, -20, 21, -22, -21, 64, -23, -18, 23, -28, 5, 18, -5, -8, 9, -10, -9, 28, -19, 10, 19, -48, 17, 14, -17, 20 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The Stern polynomial B(n,x) evaluated at x=-2. See A125184. - T. D. Noe, Feb 28 2011

Self-convolution of the signed Thue-Morse sequence A106400. - Vladimir Reshetnikov, Apr 13 2018

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..10000

Maciej Gawron, Piotr Miska, Maciej Ulas, Arithmetic properties of coefficients of power series expansion of Prod_{n>=0} (1-x^(2^n))^t, arXiv:1703.01955 [math.NT], 2017.

Eric Rowland, A matrix generalization of a theorem of Fine, arXiv:1704.05872 [math.NT], 2017.

Eric Rowland, A matrix generalization of a theorem of Fine, Integers, Electronic Journal of Combinatorial Number Theory 18A (2018), #A18.

FORMULA

Euler transform of sequence b(n) where b(2^k)=-2 and zero otherwise.

G.f.: A(x) satisfies 0=f(A(x), A(x^2), A(x^3), A(x^6)) where f(u1, u2, u3, u6)=u1^3*u6 + 6*u1^2*u2*u6 + 9*u1*u2^2*u6 - u3*u2^3.

G.f.: x(Product_{k>=0} (1-x^(2^k)))^2.

G.f.: A(x) satisfies 0=f(A(x), A(x^2), A(x^4)) where f(u, v, w)=-v^3+4uvw+u^2w.

MATHEMATICA

Table[Sum[(-1)^(DigitCount[k, 2, 1] + DigitCount[n-k-1, 2, 1]), {k, 0, n-1}], {n, 1, 80}] (* Vladimir Reshetnikov, Apr 13 2018 *)

PROG

(PARI) {a(n)=local(A, m); if(n<1, 0, n--; A=1+x*O(x^n); m=1; while(m<=n, A*=(1-x^m); m*=2; ); polcoeff(A^2, n))}

CROSSREFS

Sequence in context: A227629 A183201 A082467 * A023141 A283324 A072650

Adjacent sequences:  A106404 A106405 A106406 * A106408 A106409 A106410

KEYWORD

sign,look

AUTHOR

Michael Somos, May 02 2005

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 25 23:23 EDT 2020. Contains 337346 sequences. (Running on oeis4.)