[go: up one dir, main page]

login
A276617
Square array A(n,k) = A276955(n,k)/k!, read by descending antidiagonals as A(1,1), A(1,2), A(2,1), A(1,3), A(2,2), A(3,1), etc.
6
1, 1, 3, 1, 4, 4, 1, 5, 6, 5, 1, 6, 8, 7, 7, 1, 7, 10, 9, 13, 9, 1, 8, 12, 11, 21, 16, 10, 1, 9, 14, 13, 31, 25, 18, 11, 1, 10, 16, 15, 43, 36, 28, 19, 13, 1, 11, 18, 17, 57, 49, 40, 29, 25, 15, 1, 12, 20, 19, 73, 64, 54, 41, 41, 28, 16, 1, 13, 22, 21, 91, 81, 70, 55, 61, 45, 30, 17, 1, 14, 24, 23, 111, 100, 88, 71, 85, 66, 48, 31, 18
OFFSET
1,3
FORMULA
A(n,k) = A276955(n,k)/k!
EXAMPLE
The top left corner of the array:
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19
4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36
5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37
7, 13, 21, 31, 43, 57, 73, 91, 111, 133, 157, 183, 211, 241, 273, 307, 343
9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, 256, 289, 324, 361
PROG
(Scheme)
(define (A276617 n) (A276617bi (A002260 n) (A004736 n)))
(define (A276617bi row col) (/ (A276955bi row col) (A000142 col)))
CROSSREFS
Transpose: A276616.
Columns 1-3: A273670, A276931, A276934.
Row 1: A000012, Row 2: n+2, Row 3: 2n+2, Row 4: 2n+3 (for n >= 1).
Row 5: A002061 (from a(3)=7 onward).
Row 6: squares (A000290, from a(3)=9 onward).
Row 7: A028552 (from a(2)=10 onward).
Row 8: A028387 (from a(2)=11 onward).
Sequence in context: A373987 A089554 A376276 * A276616 A286623 A246340
KEYWORD
nonn,base,tabl
AUTHOR
Antti Karttunen, Sep 22 2016
STATUS
approved