This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A008875 #29 Jul 08 2025 01:21:57 %S A008875 95,286,143,430,215,646,323,970,485,1456,728,364,182,91,274,137,412, %T A008875 206,103,310,155,466,233,700,350,175,526,263,790,395,1186,593,1780, %U A008875 890,445,1336,668,334,167,502,251,754,377,1132,566,283,850,425,1276,638,319,958,479,1438,719,2158,1079,3238 %N A008875 3x+1 sequence starting at 95. %D A008875 R. K. Guy, Unsolved Problems in Number Theory, E16. %H A008875 T. D. Noe, <a href="/A008875/b008875.txt">Table of n, a(n) for n=0..105</a> %H A008875 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a> %F A008875 a(n) = A008874(n + 2). %p A008875 f := proc(n) option remember; if n = 0 then 95; elif f(n-1) mod 2 = 0 then f(n-1)/2 else 3*f(n-1)+1; fi; end; %t A008875 NestList[If[EvenQ[#],#/2,3#+1]&,95,60] (* _Harvey P. Dale_, Dec 02 2012 *) %o A008875 (Haskell) %o A008875 a008875 n = a008875_list !! n %o A008875 a008875_list = drop 2 a008874_list %o A008875 -- _Reinhard Zumkeller_, Aug 30 2012 %o A008875 (Magma) [n eq 1 select 95 else IsOdd(Self(n-1)) select 3*Self(n-1)+1 else Self(n-1) div 2: n in [1..70]]; // _Vincenzo Librandi_, Jul 29 2014 %Y A008875 Cf. A006370, A008874. %Y A008875 Row 95 of A347270. %K A008875 nonn %O A008875 0,1 %A A008875 _N. J. A. Sloane_ %E A008875 More terms from Larry Reeves (larryr(AT)acm.org), Apr 27 2001