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A076334 Differences between successive squarefree kernels. 1
1, 1, -1, 3, 1, 1, -5, 1, 7, 1, -5, 7, 1, 1, -13, 15, -11, 13, -9, 11, 1, 1, -17, -1, 21, -23, 11, 15, 1, 1, -29, 31, 1, 1, -29, 31, 1, 1, -29, 31, 1, 1, -21, -7, 31, 1, -41, 1, 3, 41, -25, 27, -47, 49, -41, 43, 1, 1, -29, 31, 1, -41, -19, 63, 1, 1, -33, 35, 1, 1, -65, 67, 1, -59, 23, 39 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A007947(n+1) - A007947(n).

G.f.: -1 + (1 - x)*Sum_{k>=1} phi(k)*mu(k)^2*x^(k-1)/(1 - x^k). - Ilya Gutkovskiy, Apr 15 2017

MATHEMATICA

Drop[CoefficientList[Series[-1 + (1 - x)*Sum[EulerPhi[k] MoebiusMu[k]^2*x^(k - 1)/(1 - x^k), {k, 100}], {x, 0, 100}], x], 1] (* Indranil Ghosh, Apr 16 2017 *)

PROG

(PARI) x='x+O('x^100); Vec(-1 + (1 - x)*sum(k=1, 100, eulerphi(k)*moebius(k)^2*x^(k - 1)/(1 - x^k))) \\ Indranil Ghosh, Apr 16 2017

CROSSREFS

Cf. A007947.

Sequence in context: A201669 A069002 A245369 * A014475 A320436 A135228

Adjacent sequences:  A076331 A076332 A076333 * A076335 A076336 A076337

KEYWORD

sign

AUTHOR

Reinhard Zumkeller, Nov 06 2002

STATUS

approved

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Last modified December 1 06:09 EST 2020. Contains 338833 sequences. (Running on oeis4.)