A121388 Table read by antidiagonals which classifies the proper odd numbers by form (i,j) where i and j are the number of prime factors of the form 4k-1 and 4k+1 respectively.

3, 5, 7, 9, 13, 11, 15, 21, 17, 19, 25, 35, 33, 29, 23, 27, 65, 39, 49, 37, 31, 45, 63, 85, 51, 57, 41, 43, 75, 105, 99, 145, 55, 69, 53, 47, 125, 175, 117, 147, 169, 87, 77, 61, 59, 81, 325, 195, 153, 171, 185, 91, 93, 73, 67, 135, 189, 425, 255, 165, 207, 205, 95, 121, 89

Offset

1,1

Links

Table of n, a(n) for n=1..65.

Example

Table begins:
Row(i,j)
1: (1,0) 3,7,11,19,23,31,43,47,59,67,71,79,83,103,... (A002145)
2: (0,1) 5,13,17,29,37,41,53,61,73,89,97,101,109,... (A002144)
3: (2,0) 9,21,33,49,57,69,77,93,121,129,133,141,... (A107978)
4: (1,1) 15,35,39,51,55,87,91,95,111,115,119,... (A080774)
5: (0,2) 25,65,85,145,169,185,205,221,265,289,... (A121387)
6: (3,0) 27,63,99,147,171,207,231,279,343,...
7: (2,1) 45,105,117,153,165,245,261,273,...
8: (1,2) 75,175,195,255,275,435,455,...
9: (0,3) 125,325,425,725,845,925,...
10:(4,0) 81,189,297,441,513,...
11:(3,1) 135,315,351,459,...
12:(2,2) 225,525,585,...
13:(1,3) 375,875,...
14:(0,4) 625,...

Crossrefs

Cf. A120027. Subsequences begin A002145 A002144 A107978 A080774 A121387.

Sequence in context: A100432 A261033 A145341 * A161700 A245212 A063081

Adjacent sequences: A121385 A121386 A121387 * A121389 A121390 A121391

Keyword

nonn,tabl

Author

Alford Arnold, Jul 26 2006

Extensions

Edited, corrected and extended by Ray Chandler, Aug 08 2010

Status

approved