cp's OEIS Frontend

A371095 Array A read by upward antidiagonals in which the entry A(n,k) in row n and column k is defined by A(1, k) = 8*k-7, and A(n+1, k) = R(A(n, k)), n,k >= 1, where Reduced Collatz function R(n) gives the odd part of 3n+1.

%I A371095 #7 Apr 24 2024 13:58:36
%S A371095 1,1,9,1,7,17,1,11,13,25,1,17,5,19,33,1,13,1,29,25,41,1,5,1,11,19,31,
%T A371095 49,1,1,1,17,29,47,37,57,1,1,1,13,11,71,7,43,65,1,1,1,5,17,107,11,65,
%U A371095 49,73,1,1,1,1,13,161,17,49,37,55,81,1,1,1,1,5,121,13,37,7,83,61,89,1,1,1,1,1,91,5,7,11,125,23,67,97
%N A371095 Array A read by upward antidiagonals in which the entry A(n,k) in row n and column k is defined by A(1, k) = 8*k-7, and A(n+1, k) = R(A(n, k)), n,k >= 1, where Reduced Collatz function R(n) gives the odd part of 3n+1.
%H A371095 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a>
%e A371095 Array begins:
%e A371095 n\k|  1   2   3   4   5    6   7   8   9   10  11   12   13   14   15   16
%e A371095 ---+------------------------------------------------------------------------
%e A371095 1  |  1,  9, 17, 25, 33,  41, 49, 57, 65,  73, 81,  89,  97, 105, 113, 121,
%e A371095 2  |  1,  7, 13, 19, 25,  31, 37, 43, 49,  55, 61,  67,  73,  79,  85,  91,
%e A371095 3  |  1, 11,  5, 29, 19,  47,  7, 65, 37,  83, 23, 101,  55, 119,   1, 137,
%e A371095 4  |  1, 17,  1, 11, 29,  71, 11, 49,  7, 125, 35,  19,  83, 179,   1, 103,
%e A371095 5  |  1, 13,  1, 17, 11, 107, 17, 37, 11,  47, 53,  29, 125, 269,   1, 155,
%e A371095 6  |  1,  5,  1, 13, 17, 161, 13,  7, 17,  71,  5,  11,  47, 101,   1, 233,
%e A371095 7  |  1,  1,  1,  5, 13, 121,  5, 11, 13, 107,  1,  17,  71,  19,   1, 175,
%e A371095 8  |  1,  1,  1,  1,  5,  91,  1, 17,  5, 161,  1,  13, 107,  29,   1, 263,
%e A371095 9  |  1,  1,  1,  1,  1, 137,  1, 13,  1, 121,  1,   5, 161,  11,   1, 395,
%e A371095 10 |  1,  1,  1,  1,  1, 103,  1,  5,  1,  91,  1,   1, 121,  17,   1, 593,
%e A371095 11 |  1,  1,  1,  1,  1, 155,  1,  1,  1, 137,  1,   1,  91,  13,   1, 445,
%e A371095 12 |  1,  1,  1,  1,  1, 233,  1,  1,  1, 103,  1,   1, 137,   5,   1, 167,
%e A371095 13 |  1,  1,  1,  1,  1, 175,  1,  1,  1, 155,  1,   1, 103,   1,   1, 251,
%e A371095 14 |  1,  1,  1,  1,  1, 263,  1,  1,  1, 233,  1,   1, 155,   1,   1, 377,
%e A371095 15 |  1,  1,  1,  1,  1, 395,  1,  1,  1, 175,  1,   1, 233,   1,   1, 283,
%e A371095 16 |  1,  1,  1,  1,  1, 593,  1,  1,  1, 263,  1,   1, 175,   1,   1, 425,
%o A371095 (PARI)
%o A371095 up_to = 91;
%o A371095 R(n) = { n = 1+3*n; n>>valuation(n, 2); };
%o A371095 A371095sq(n,k) = if(1==n,8*k-7,R(A371095sq(n-1,k)));
%o A371095 A371095list(up_to) = { my(v = vector(up_to), i=0); for(a=1,oo, for(col=1,a, i++; if(i > up_to, return(v)); v[i] = A371095sq((a-(col-1)),col))); (v); };
%o A371095 v371095 = A371095list(up_to);
%o A371095 A371095(n) = v371095[n];
%Y A371095 Cf. A017077 (row 1), A016921 (row 2), A075677.
%Y A371095 Cf. also A371096, A371097.
%K A371095 nonn,tabl,easy
%O A371095 1,3
%A A371095 _Antti Karttunen_, Apr 24 2024