|
Search: id:A059428
|
|
|
| A059428 |
|
Number of points of rotation in a prime block spiral. |
|
+0
1
|
|
| 2, 3, 5, 11, 17, 29, 41, 59, 73, 101, 127, 157, 191, 229, 269, 313, 367, 421, 467, 547, 607, 673, 751, 829, 919, 1013, 1093, 1201, 1297, 1429, 1523, 1621, 1753, 1889, 2027, 2153, 2309, 2441, 2621, 2749, 2909, 3089, 3299, 3463, 3623, 3821, 4007, 4217, 4421
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Analogous to A002620 except primes are substituted for the natural numbers.
|
|
FORMULA
|
Arrange primes in a block spiral formation. a(n) is determined by the point of rotation to allow for continuation of the sequence.
|
|
EXAMPLE
|
Spiral begins:
(73)--79--83--89---97--(101)
..|......................|
.71..(17)-19--23--(29) etc.
..|....|............|
.67...13..(2)-(3)..31
..|....|.......|....|
.61..(11)--7--(5)..37
..|.................|
(59)--53--47--43--(41)
|
|
MAPLE
|
A059428 := proc(n) RETURN(ithprime(1+floor(n^2/4))) end: # Francisco Salinas (franciscodesalinas(AT)hotmail.com), Jan 05 2002
|
|
CROSSREFS
|
Sequence in context: A073534 A063091 A124588 this_sequence A084571 A055498 A073021
Adjacent sequences: A059425 A059426 A059427 this_sequence A059429 A059430 A059431
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Jason Earls (zevi_35711(AT)yahoo.com), Mar 15 2001
|
|
EXTENSIONS
|
More terms from Larry Reeves (larryr(AT)acm.org), Apr 19 2001
|
|
|
Search completed in 0.002 seconds
|
