A342816 Numbers of the form (2^(2*j + 6*k + 10) - 2^(2*j + 2) - 3)/9, with j,k >= 0.

113, 453, 1813, 7253, 7281, 29013, 29125, 116053, 116501, 464213, 466005, 466033, 1856853, 1864021, 1864133, 7427413, 7456085, 7456533, 29709653, 29824341, 29826133, 29826161, 118838613, 119297365, 119304533, 119304645, 475354453, 477189461, 477218133

Offset

1,1

Comments

Sequence is a subsequence of A198584. When any term is iterated using the Collatz function, the last odd integer in the trajectory before 1 is of the form (4^(3*m + 4) - 1)/3.

Links

Table of n, a(n) for n=1..29.

Satya Das, Extension of speeded up Collatz map to the real line

Mathematica

Take[Sort[Flatten[Table[(2^(2n1+6n2+10) - 2^(2n1+2) - 3)/9, {n1, 0, 20}, {n2, 0, 20}]]], 50]

Prog

(Python)
seq=[]
for n1 in range(20):
    for n2 in range(20):
        n=(2**(2*n1+6*n2+10) - 2**(2*n1+2) - 3)/9
        seq.append(n)
seq.sort()
print(seq[0:50])

Crossrefs

Union with A342815 gives A198584.

Sequence in context: A365581 A111013 A300537 * A353957 A142850 A203722

Adjacent sequences: A342813 A342814 A342815 * A342817 A342818 A342819

Keyword

nonn,easy

Author

Satya Das, Mar 22 2021

Status

approved