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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.)