login
A245709
Fixed points of A245705 and A245706.
5
1, 2, 3, 4, 5, 6, 8, 10, 12, 16, 20, 24, 32, 40, 43, 48, 53, 64, 80, 86, 96, 106, 128, 160, 172, 192, 212, 249, 256, 320, 344, 384, 417, 424, 498, 512, 640, 688, 768, 834, 848, 996, 1024, 1280, 1321, 1376, 1536, 1668, 1696, 1992, 2048, 2560, 2642, 2752, 3072, 3336, 3392, 3984, 4096, 5120, 5284, 5504, 5545, 6144, 6672, 6784, 6827, 7081, 7968, 8192
OFFSET
1,2
COMMENTS
The odd terms less than 2^25 are: 1, 3, 5, 43, 53, 249, 417, 1321, 5545, 6827, 7081, 8535, 1485465, 1876261, 3298409, 13937375.
Contains also all such numbers k that A245608(k) = A245708(k), because that condition implies that A245607(A245708(k)) = k = A245707(A245608(k)). Conjecture: contains no numbers outside of that set, that is, for all n, A245608(a(n)) = A245708(a(n)).
LINKS
PROG
(PARI)
isA245709(n) = (A245705(n) == n);
i=0; for(n=1, 2^20, if(isA245709(n), i++; write("b245709.txt", i, " ", n)))
\\ Alternative implementation, based on given conjecture:
isA245709v2(n) = (A245608(n) == A245708(n));
i=0; for(n=1, 2^25, if(isA245709v2(n), i++; write("b245709v2.txt", i, " ", n)))
(Scheme, with Antti Karttunen's IntSeq-library, two alternative implementations)
(define A245709 (FIXED-POINTS 1 1 A245705))
(define A245709 (MATCHING-POS 1 1 (lambda (k) (= (A245608 k) (A245708 k)))))
CROSSREFS
A000079 is a subsequence.
Sequence in context: A015702 A362127 A364960 * A364565 A364548 A364544
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 30 2014
STATUS
approved