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A063750 Number of divisors (A000005) of the Wonderful Demlo numbers A002477. 1
1, 3, 9, 9, 9, 243, 9, 81, 45, 81, 9, 2187, 27, 81, 729, 729, 9, 10935, 3, 2187, 2187, 1215, 3, 59049, 243, 729, 567, 6561, 243, 1594323, 27, 177147, 729, 729, 2187, 295245, 27, 27, 729, 177147, 81, 7971615, 81, 98415, 32805, 729 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..80

FORMULA

a(n) = A000005(A002477(n)) = d(((10^n-1)/9)^2). - M. F. Hasler, Nov 18 2017

MAPLE

a:=n->((10^n-1)/9)^2: A063750:=[seq(numtheory[tau](a(n)), n=1..50)]; # Muniru A Asiru, Feb 17 2018

MATHEMATICA

Array[DivisorSigma[0, FromDigits[PadRight[{}, #, 1]]^2] &, 46] (* Michael De Vlieger, Nov 18 2017, after Harvey P. Dale at A002477 *)

PROG

(PARI) vector(45, n, numdiv((10^n\9)^2) ) \\ Edited by M. F. Hasler, Nov 18 2017

(PARI) apply( A063750=n->numdiv((10^n\9)^2), [1..80]) \\ M. F. Hasler, Nov 18 2017

(GAP) a:=n->((10^n-1)/9)^2;;  A063750:=List([1..50], n->Tau(a(n))); # Muniru A Asiru, Feb 17 2018

CROSSREFS

Cf. A002477 = A000290(A002275), A000005.

Sequence in context: A100401 A004166 A110759 * A143225 A223195 A203600

Adjacent sequences:  A063747 A063748 A063749 * A063751 A063752 A063753

KEYWORD

nonn

AUTHOR

Jason Earls, Aug 11 2001

EXTENSIONS

Edited and offset corrected by M. F. Hasler, Nov 18 2017

STATUS

approved

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Last modified January 17 22:51 EST 2019. Contains 319251 sequences. (Running on oeis4.)