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A307032 Permutation of the positive integers formed by moving each number the sum of its prime factors to the right. 1
1, 2, 3, 4, 5, 6, 8, 7, 9, 10, 12, 11, 14, 15, 16, 18, 13, 20, 21, 17, 24, 22, 25, 27, 19, 28, 30, 26, 32, 23, 33, 36, 35, 40, 34, 42, 29, 39, 45, 38, 48, 44, 31, 49, 50, 54, 46, 52, 51, 56, 55, 60, 37, 63, 64, 57, 41, 43, 66, 65, 70, 72, 58, 68, 75, 47, 62 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
To generate this sequence, start with a list of the positive integers. For each positive integer, calculate the sum of its prime factors (with multiplicity) and move each element that numbers of positions to the right in the sequence. This is a permutation of the positive integers. All prime numbers appear in increasing order.
LINKS
Albert ten Oever, Python program
EXAMPLE
Generation of the first five elements:
- Start with the natural numbers: 1, 2, 3, 4, 5.
- Prime factorization of those numbers: 1, 2, 3, 2*2, 5.
- Sum of prime factors: 0, 2, 3, 4, 5.
- Now move each element:
- Move 1 0 steps: 1, 2, 3, 4, 5.
- Move 2 2 steps: 1, 3, 4, 2, 5.
- Move 3 3 steps: 1, 4, 2, 5, 3.
- Move 4 4 steps: 1, 2, 5, 3, 6, 4 (needed to extend range to move 4)
- Move 5 5 steps: 1, 2, 3, 6, 4, 7, 8, 5 (needed to extend range to move 5)
- Because 6, 7, 8 and 9 are also moved to the right, the first 5 elements are: 1, 2, 3, 4, 5.
CROSSREFS
Cf. A001414 (sum of primes dividing n, with repetition).
Sequence in context: A073289 A122349 A127388 * A273859 A332073 A117332
KEYWORD
nonn
AUTHOR
Albert ten Oever, Mar 20 2019
EXTENSIONS
Corrected sequence caused by an error in the Python code generating the sequence. Edited by Albert ten Oever, Mar 24 2019
STATUS
approved

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)