Search: id:A023001 Results 1-1 of 1 results found. %I A023001 %S A023001 0,1,9,73,585,4681,37449,299593,2396745,19173961,153391689,1227133513, %T A023001 9817068105,78536544841,628292358729,5026338869833,40210710958665, %U A023001 321685687669321,2573485501354569,20587884010836553,164703072086692425 %N A023001 (8^n - 1)/7. %C A023001 Gives the (zero-based) positions of odd terms in A007556 (Mod[A007556[A0023001(n)], 2]=1). - Farideh_Firoozbakht (f.firoozbakht(AT)sci.ui.ac.ir), Jun 13 2003 %C A023001 a(n) = A033138(3n-2). - Alexandre Wajnberg (alexandre.wajnberg(AT)ulb.ac.be), May 31 2005 %C A023001 {1, 9, 73, 585, 4681, ...} is the binomial transform of A003950 . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jul 22 2005 %C A023001 Except for the first term, a(n)=8*a(n-1)+1 (with a(1)=1) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Oct 29 2009] %H A023001 Index entries for sequences related to linear recurrences with constant coefficients %H A023001 Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics. %F A023001 Also sum of cubes of divisors of 2^(n-1): a(n)=A001158[A000079(n-1)] - Labos E. (labos(AT)ana.sote.hu), Apr 10 2003 and Farideh_Firoozbakht (f.firoozbakht(AT)sci.ui.ac.ir), Jun 13 2003 %F A023001 a(0)=0, a(n)=8*a(n-1)+1 for n>0 . G.f.:x/((1-8x)*(1-x)) - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Oct 12 2006 %e A023001 Octal.............decimal (comment from Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jan 14 2007): %e A023001 0....................0 %e A023001 1....................1 %e A023001 11...................9 %e A023001 111.................73 %e A023001 1111...............585 %e A023001 11111.............4681 %e A023001 111111...........37449 %e A023001 1111111.........299593 %e A023001 11111111.......2396745 %e A023001 111111111.....19173961 %e A023001 1111111111...153391689 %e A023001 etc. ...............etc. %p A023001 a:=n->sum(8^(n-j),j=1..n): seq(a(n), n=0..20); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jan 04 2007 %t A023001 Table[(8^n-1)/7, {n, 0, m}] %o A023001 (Other) sage: [lucas_number1(n,9,8) for n in xrange(0, 21)]# [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 23 2009] %o A023001 (Other) sage: [gaussian_binomial(n,1,8) for n in xrange(0,21)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 28 2009] %Y A023001 Cf. A007556. %Y A023001 Sequence in context: A126641 A081627 A164588 this_sequence A015454 A121246 A086226 %Y A023001 Adjacent sequences: A022998 A022999 A023000 this_sequence A023002 A023003 A023004 %K A023001 easy,nonn %O A023001 0,3 %A A023001 David W. Wilson (davidwwilson(AT)comcast.net) Search completed in 0.002 seconds