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A372443
The n-th iterate of 27 with Reduced Collatz-function R, which gives the odd part of 3n+1.
15
27, 41, 31, 47, 71, 107, 161, 121, 91, 137, 103, 155, 233, 175, 263, 395, 593, 445, 167, 251, 377, 283, 425, 319, 479, 719, 1079, 1619, 2429, 911, 1367, 2051, 3077, 577, 433, 325, 61, 23, 35, 53, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
OFFSET
0,1
FORMULA
a(0) = 27; for n > 0, a(n) = R(a(n-1)), where R(n) = (3*n+1)/2^A371093(n) = A000265(3*n+1).
For n > 0, a(n) = R(A372444(n-1)) = A000265(1+3*A372444(n-1)).
PROG
(PARI)
R(n) = { n = 1+3*n; n>>valuation(n, 2); };
A372443(n) = { my(x=27); while(n, x=R(x); n--); (x); };
CROSSREFS
Column 14 of A372283, Row 13 of A256598 (but only up to the first 1).
Row 1 of A372560.
From term 47 to the first 1 same as A088593.
Sequences derived from this one or related to:
A372445 column index of a(n) in array A257852,
A372362 the 2-adic valuation of 1 + 3*a(n), equal to row index of a(n) in array A257852,
A372447 binary lengths minus 1,
A372446 a(n) xored with the term of A086893 having the same binary length,
A372453 a(n) minus the term of A086893 having the same binary length.
Sequence in context: A369252 A117103 A217008 * A355903 A124940 A272829
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 01 2024
STATUS
approved