OFFSET

1,1

COMMENTS

Sequence suggested by N. J. A. Sloane on the SeqFan mailing list. These are also the numbers n for which A230626(n) = -1 and A230627(n) = A287875(n) = 0. All currently-listed terms (those <= 3858) enter one of the two loops 1007 <-> 1269 and 1503 <-> 3751.

Further values added (Jun 19 2017) based on Sean A. Irvine's extension of the b-file for A230626.

EXAMPLE

217, 255, 945, 1007 and 1269 are in the sequence because under the map x -> A230625(x):

217 = 7*31 = binary 111*11111 -> binary 11111111 = 255

255 = 3*5*17 = binary 11*101*10001 -> binary 1110110001 = 945

945 = 3^3*5*7 = binary 11^11*101*111 -> binary 1111101111 = 1007

1007 = 19*53 = binary 10011*110101 -> binary 10011110101 = 1269

1269 = 3^3*47 = binary 11^11*101111 -> binary 1111101111 = 1007

CROSSREFS

KEYWORD

nonn,base

AUTHOR

David J. Seal, Jun 18 2017

EXTENSIONS

a(43)-a(48) from Chai Wah Wu, Jul 13 2017

STATUS

approved