

A234588


Lexicographically earliest sequence S with property that a(n) is the a(n)th absolute first difference of S.


0



1, 2, 4, 5, 9, 14, 8, 10, 18, 27, 17, 6, 11, 15, 29, 44, 19, 36, 54, 35, 21, 42, 23, 46, 25, 50, 28, 55, 83, 112, 31, 62, 33, 66, 37, 72, 108, 71, 39, 78, 41, 82, 124, 45, 89, 134, 88, 48, 96, 51, 101, 152, 53, 106, 160, 105, 57, 114, 59, 118, 61, 122, 184, 64
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


COMMENTS

A kind of selfdescribing sequence.
Recamán's sequence A005132 is also selfdescribing in this sense, but comes lexicographically after this one (and you have to drop the initial "0").
If we want S to be monotonically increasing, we get A063733.


REFERENCES

Eric Angelini, Posting to Sequence Fans Mailing List, Nov 26, 2010


LINKS

Table of n, a(n) for n=1..64.


EXAMPLE

If n = 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 ...
a(n) = 1 2 4 5 9 14 8 10 18 27 17, 6 11 15 29 44 19 36 54 35 21 42 23 46 25 50 28 55 ...
diff = 1 2 1 4 5 6 2 8 9 10 11 5 4 14 15 25 17 18 19 14 21 19 23 21 25 22
drank= 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
hit: * * * * * * * * * * * * *
S is tricky to compute; the rule for a(n+1) is "always use the smallest integer not yet in S and not leading to a contradiction".
'14' is in S and '14' says: "The 14th absolute first difference in S equals 14"  which is true.


CROSSREFS

Cf. A005132, A063733.
Sequence in context: A068372 A068370 A060167 * A118550 A126697 A162406
Adjacent sequences: A234585 A234586 A234587 * A234589 A234590 A234591


KEYWORD

nonn


AUTHOR

Eric Angelini, Dec 31 2013


EXTENSIONS

More terms from Jon E. Schoenfield, Jan 11 2014


STATUS

approved



