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A051028 Ramanujan's a-series. 3
1, 135, 11161, 926271, 76869289, 6379224759, 529398785665, 43933719985479, 3645969360009049, 302571523160765631, 25109790452983538281, 2083810036074472911735, 172931123203728268135681 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

The "amazing" identity of Ramanujan is a(n)^3 + b(n)^3 = c(n)^3 + (-1)^n, where a(n)=A051028(n), b(n)=A051029(n) and c(n)=A051030(n). - Emeric Deutsch (deutsch(AT)duke.poly.edu), Oct 14 2006

REFERENCES

M. D. Hirschhorn, A Proof in the Spirit of Zeilberger of an Amazing Identity of Ramanujan.

Jung Hun Han and Michael D. Hirschhorn, Another look at an amazing identity of Ramanujan, Math. Magazine, 79, No. 2, 2006, 302-304.

LINKS

M. D. Hirschhorn, Ramanujan and Fermat's Last Theorem

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

FORMULA

G.f.: f(x)=(1+53x+9x^2)/(1-82x-82x^2+x^3).

X(n+1)=AX(n), where X(n)=transpose(A051028(n), A051029(n), A051030(n)) and A = matrix (3,3,[63,104,-68; 64,104,-67; 80,131,-85)]). - Emeric Deutsch (deutsch(AT)duke.poly.edu), Oct 14 2006

MAPLE

g:=(1+53*x+9*x^2)/(1-82*x-82*x^2+x^3): gser:=series(g, x=0, 20): seq(coeff(gser, x, n), n=0..12); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Oct 14 2006

CROSSREFS

Cf. A051029, A051030.

Sequence in context: A195671 A004005 A143404 * A076011 A132054 A106175

Adjacent sequences:  A051025 A051026 A051027 * A051029 A051030 A051031

KEYWORD

nonn

AUTHOR

Eric Weisstein (eric(AT)weisstein.com)

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Last modified February 14 22:30 EST 2012. Contains 205678 sequences.