[seqfan] Re: Twindragon & other nonconventional bases.
Kevin Ryde
user42_kevin at yahoo.com.au
Mon Sep 12 01:57:26 CEST 2016
antti.karttunen at gmail.com (Antti Karttunen) writes:
>
> I mean that it is almost futile to search with keywords like base i-1
> entered into the OEIS search field. (Please try it: 4856 results found.) So
> at least the (normally invisible) anchor-part of the index-entry should be
> something searchable. Maybe #twindragon would work perfectly well there?
Oh I think I only searched numbers and grepped the names file. Dunno
what words could most help. Maybe "complex base" to start, but within
it many possible bases and digits. Searching that is a bit sparse now
but includes some of some more existing sequences,
A193239 reverse-add steps to palindrome N
A193240 reverse-add trajectory of binary 110
A193241 reverse-add trajectory of binary 10110
A193306 reverse-subtract steps to 0 (plain-rev)
A193307 reverse-subtract steps to 0 (rev-plain)
A256441 N on negative X axis
A271472 N on X axis, in binary
Did anyone answer on Gaussian primes? With some gp I make (medium
confidence, and not noticing much pattern),
2, 5, 6, 9, 11, 13, 14, 15, 17, 19, 21, 23, 25, 27, 31, 33, 37, 39,
41, 43, 49, 51, 53, 57, 58, 59, 63, 69, 71, 73, 77, 81, 83, 89, 97,
99, 101, 111, 113, 117, 119, 123, 127, 129, 131, 133, 137, 139, 141
or increments
3, 1, 3, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 4, 2, 4, 2, 2, 2, 6, 2, 2, 4,
1, 1, 4, 6, 2, 2, 4, 4, 2, 6, 8, 2, 2, 10, 2, 4, 2, 4, 4, 2, 2, 2, 4,
2, 2
or binary
10, 101, 110, 1001, 1011, 1101, 1110, 1111, 10001, 10011, 10101,
10111, 11001, 11011, 11111, 100001, 100101, 100111, 101001, 101011,
110001, 110011, 110101, 111001, 111010, 111011, 111111, 1000101,
1000111, 1001001, 1001101, 1010001, 1010011, 1011001, 1100001,
1100011, 1100101, 1101111, 1110001, 1110101, 1110111, 1111011,
1111111, 10000001, 10000011, 10000101, 10001001, 10001011, 10001101
An even n is even z (x+i*y with x+y even), so the only evens are n = 2,
6, 14, 58 which are z = +/- 1 +/- i.
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