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Search: id:A101917
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A101917 G.f. satisfies: A(x) = 1/(1 + x*A(x^7)) and also the continued fraction: 1+x*A(x^8) = [1;1/x,1/x^7,1/x^49,1/x^343,...,1/x^(7^(n-1)),...]. +0
3
1, -1, 1, -1, 1, -1, 1, -1, 2, -3, 4, -5, 6, -7, 8, -10, 13, -17, 22, -28, 35, -43, 53, -66, 83, -105, 133, -168, 211, -264, 330, -413, 518, -651, 819, -1030, 1294, -1624, 2037, -2555, 3206, -4025, 5055, -6349, 7973, -10010, 12565, -15771, 19796, -24851, 31200, -39173, 49183, -61748, 77519, -97315, 122166 (list; graph; listen)
OFFSET

0,9

FORMULA

G.f.: (1+x^6) / (1+x+x^7) (conjectured). - Ralf Stephan, May 17 2007

PROGRAM

(PARI) {a(n)=local(A); A=1-x; for(i=1, n\7+1, A=1/(1+x*subst(A, x, x^7)+x*O(x^n))); polcoeff(A, n, x)} (PARI) {a(n)=local(M=contfracpnqn(concat(1, vector(ceil(log(n+1)/log(7))+1, n, 1/x^(7^(n-1)))))); polcoeff(M[1, 1]/M[2, 1]+x*O(x^(8*n+1)), 8*n+1)}

CROSSREFS

Cf. A101912-A101916, A101918.

Sequence in context: A071218 A017901 A005709 this_sequence A127273 A143287 A033073

Adjacent sequences: A101914 A101915 A101916 this_sequence A101918 A101919 A101920

KEYWORD

sign

AUTHOR

Paul D. Hanna (pauldhanna(AT)juno.com), Dec 20 2004

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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