cp's OEIS Frontend

A061987 Number of times n-th distinct value is repeated in sequence b(k) = 1 + b(floor(k/2)) + b(floor(k/3)) with b(0) = 0, i.e., in A061984; also number of times n-th distinct row is repeated in square array T(n,k) = T(n-1,k) + T(n-1,floor(k/2)) + T(n-1,floor(k/3)) with T(0,0) = 1, i.e., in A061980.

%I A061987 #15 Feb 16 2025 08:32:44
%S A061987 1,1,1,1,2,2,1,3,4,2,6,3,5,4,12,6,10,8,9,15,12,20,16,18,30,24,27,13,
%T A061987 32,36,60,48,54,26,64,72,81,39,96,108,52,128,144,162,78,192,216,104,
%U A061987 139,117,288,324,156,384,432,208,278,234,576,648,312,417,351,864,416,556
%N A061987 Number of times n-th distinct value is repeated in sequence b(k) = 1 + b(floor(k/2)) + b(floor(k/3)) with b(0) = 0, i.e., in A061984; also number of times n-th distinct row is repeated in square array T(n,k) = T(n-1,k) + T(n-1,floor(k/2)) + T(n-1,floor(k/3)) with T(0,0) = 1, i.e., in A061980.
%C A061987 For n > 0: a(n) = A003586(n+1) - A003586(n) and a(A084791(n)) = A084788(n).
%C A061987 Also number of times A160519(n+1) is repeated in A088468. - _Reinhard Zumkeller_, May 16 2009
%C A061987 In the 14th century Levi Ben Gerson proved that a(n) > 1 for all n > 6; see A003586, A235365, A235366, A236210. - _Jonathan Sondow_, Jan 20 2014
%H A061987 Reinhard Zumkeller, <a href="/A061987/b061987.txt">Table of n, a(n) for n = 0..100</a>
%H A061987 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SmoothNumber.html">Smooth Number</a>
%F A061987 a(n) = A061986(A061985(n)).
%o A061987 (Haskell)
%o A061987 import Data.List (group)
%o A061987 a061987 n = a061987_list !! n
%o A061987 a061987_list = map length $ group a061984_list
%o A061987 -- _Reinhard Zumkeller_, Jan 11 2014
%K A061987 nonn
%O A061987 0,5
%A A061987 _Henry Bottomley_, May 24 2001
%E A061987 More terms from _Reinhard Zumkeller_, Jun 03 2003