A371095 - OEIS

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.

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, 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, 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

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OFFSET

1,3

LINKS

Table of n, a(n) for n=1..91.

Index entries for sequences related to 3x+1 (or Collatz) problem

EXAMPLE

Array begins:

n\k| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

---+------------------------------------------------------------------------

1 | 1, 9, 17, 25, 33, 41, 49, 57, 65, 73, 81, 89, 97, 105, 113, 121,

2 | 1, 7, 13, 19, 25, 31, 37, 43, 49, 55, 61, 67, 73, 79, 85, 91,

3 | 1, 11, 5, 29, 19, 47, 7, 65, 37, 83, 23, 101, 55, 119, 1, 137,

4 | 1, 17, 1, 11, 29, 71, 11, 49, 7, 125, 35, 19, 83, 179, 1, 103,

5 | 1, 13, 1, 17, 11, 107, 17, 37, 11, 47, 53, 29, 125, 269, 1, 155,

6 | 1, 5, 1, 13, 17, 161, 13, 7, 17, 71, 5, 11, 47, 101, 1, 233,

7 | 1, 1, 1, 5, 13, 121, 5, 11, 13, 107, 1, 17, 71, 19, 1, 175,

8 | 1, 1, 1, 1, 5, 91, 1, 17, 5, 161, 1, 13, 107, 29, 1, 263,

9 | 1, 1, 1, 1, 1, 137, 1, 13, 1, 121, 1, 5, 161, 11, 1, 395,

10 | 1, 1, 1, 1, 1, 103, 1, 5, 1, 91, 1, 1, 121, 17, 1, 593,

11 | 1, 1, 1, 1, 1, 155, 1, 1, 1, 137, 1, 1, 91, 13, 1, 445,

12 | 1, 1, 1, 1, 1, 233, 1, 1, 1, 103, 1, 1, 137, 5, 1, 167,

13 | 1, 1, 1, 1, 1, 175, 1, 1, 1, 155, 1, 1, 103, 1, 1, 251,

14 | 1, 1, 1, 1, 1, 263, 1, 1, 1, 233, 1, 1, 155, 1, 1, 377,

15 | 1, 1, 1, 1, 1, 395, 1, 1, 1, 175, 1, 1, 233, 1, 1, 283,

16 | 1, 1, 1, 1, 1, 593, 1, 1, 1, 263, 1, 1, 175, 1, 1, 425,

PROG

(PARI)

up_to = 91;

R(n) = { n = 1+3*n; n>>valuation(n, 2); };

A371095sq(n, k) = if(1==n, 8*k-7, R(A371095sq(n-1, k)));

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); };

v371095 = A371095list(up_to);

A371095(n) = v371095[n];

CROSSREFS

Cf. A017077 (row 1), A016921 (row 2), A075677.

Cf. also A371096, A371097.

Sequence in context: A019948 A154207 A200101 * A084002 A376968 A339605

Adjacent sequences: A371092 A371093 A371094 * A371096 A371097 A371098

KEYWORD

nonn,tabl,easy

AUTHOR

Antti Karttunen, Apr 24 2024

STATUS

approved