OFFSET
1,2
COMMENTS
The fixed points begin 1, 8, 78, 314, 1373, 8822, 10247, 21935; it is likely there are infinitely more. The sequence is conjectured to be a permutation of the positive integers.
LINKS
Scott R. Shannon, Table of n, a(n) for n = 1..10000
EXAMPLE
a(5) = 57 as a(4) = 15 and sopfr(|57 - 15|) = sopfr(42) = 12, while sopfr(57 + 15) = sopfr(72) = 12.
CROSSREFS
KEYWORD
nonn
AUTHOR
Scott R. Shannon, Feb 20 2024
STATUS
approved