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A076131 a(n) = 2^n*a(n-1)+1, a(0) = 0. 6
0, 1, 5, 41, 657, 21025, 1345601, 172236929, 44092653825, 22575438758401, 23117249288602625, 47344126543058176001, 193921542320366288900097, 1588605274688440638669594625, 26027708820495411423962638336001 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Base-2 expansion is same as base 10 expansion of A076127.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..80

FORMULA

a(n)=floor(c*2^((n+1)*(n+2)/2)) where c =sum(k>=1, 1/2^A000217(k))=0.6416325... - Benoit Cloitre, Nov 01 2002

MATHEMATICA

a[0] = 0; a[n_] := 2^n a[n - 1] + 1; Table[ a[n], {n, 0, 13}]

PROG

(PARI) a(n)=if(n<0, 0, subst(Polrev(Vec(sum(k=1, n, x^(k*(k+1)/2)))), x, 2))

(PARI) a(n)=if(n<1, 0, 1+a(n-1)*2^n)

CROSSREFS

Cf. A000217, A073587, A076127, A190405.

Sequence in context: A104344 A100288 A076094 * A003719 A181033 A189997

Adjacent sequences:  A076128 A076129 A076130 * A076132 A076133 A076134

KEYWORD

easy,nonn,base

AUTHOR

Kyle Hunter (hunterk(AT)raytheon.com), Oct 31 2002

EXTENSIONS

Edited and extended by Robert G. Wilson v, Oct 31 2002

Formula corrected by Vaclav Kotesovec, Aug 11 2012

STATUS

approved

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Last modified August 12 04:52 EDT 2022. Contains 356067 sequences. (Running on oeis4.)