A259031 Smallest m such that |A259029(m)| = n.

3, 1, 16, 192, 768, 3072, 12288, 49152, 196608, 786432, 3145728, 12582912, 50331648, 201326592, 805306368, 3221225472, 12884901888, 51539607552

Offset

0,1

Comments

|A259029(a(n))| = n and |A259029(m)| != n for m < a(n).

Links

Table of n, a(n) for n=0..17.

Example

.   n |        a(n)            | A259029(a(n)) | A259024(a(n))
. ----+------------------------+---------------+--------------
.   0 |           3 | 3*2^0    |            0  |           -1
.   1 |           1 |   2^0    |            1  |            1
.   2 |          16 |   2^4    |            2  |            1
.   3 |         192 | 3*2^6    |           -3  |           -1
.   4 |         768 | 3*2^8    |           -4  |           -1
.   5 |        3072 | 3*2^10   |           -5  |           -1
.   6 |       12288 | 3*2^12   |           -6  |           -1
.   7 |       49152 | 3*2^14   |           -7  |           -1
.   8 |      196608 | 3*2^16   |           -8  |           -1
.   9 |      786432 | 3*2^18   |           -9  |           -1
.  10 |     3145728 | 3*2^20   |          -10  |           -1
.  11 |    12582912 | 3*2^22   |          -11  |           -1
.  12 |    50331648 | 3*2^24   |          -12  |           -1
.  13 |   201326592 | 3*2^26   |          -13  |           -1
.  14 |   805306368 | 3*2^28   |          -14  |           -1
.  15 |  3221225472 | 3*2^30   |          -15  |           -1
.  16 | 12884901888 | 3*2^32   |          -16  |           -1
.  17 | 51539607552 | 3*2^34   |          -17  |           -1  .

Prog

(Haskell)
import Data.List (elemIndex); import Data.Maybe (fromJust)
a259031 = (+ 1) . fromJust . (`elemIndex` (map abs a259029_list))
(PARI) g(n) = {my(f = factor(n), p, e); prod(i = 1, #f~, p = f[i, 1]; e = f[i, 2]; if(p == 2, (1 + (-1)^e)/2, if(p==3, if(e==1, -1, 0), if(p%6 == 1, 1, (-1)^e)))); } \\ A259029
lista(len) = {my(v=vector(len), s=0, t, k=1, c=0); while(c < len, s += g(k); t = abs(s)+1; if(t <= len && v[t] == 0, c++; v[t] = k); k++); v} \\ Amiram Eldar, Sep 02 2023

Crossrefs

Cf. A259029, A259024.

Sequence in context: A288265 A096611 A176666 * A259686 A350079 A162313

Adjacent sequences: A259028 A259029 A259030 * A259032 A259033 A259034

Keyword

nonn

Author

Reinhard Zumkeller, Jun 17 2015

Extensions

a(12)-a(17) from Amiram Eldar, Sep 02 2023

Status

approved