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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 (list; graph; refs; listen; history; text; internal format)
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

Antti Karttunen, Table of n, a(n) for n = 1..230

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.

Cf. A245705, A245706, A245608, A245708, A029747, A244154.

Sequence in context: A018541 A018293 A015702 * A253789 A029747 A095381

Adjacent sequences:  A245706 A245707 A245708 * A245710 A245711 A245712

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jul 30 2014

STATUS

approved

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Last modified September 27 11:57 EDT 2021. Contains 347689 sequences. (Running on oeis4.)