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A286234
Square array A(n,k) = P(A000010(k), floor((n+k-1)/k)), read by descending antidiagonals as A(1,1), A(1,2), A(2,1), etc. Here P is a two-argument form of sequence A000027 used as a pairing function N x N -> N.
4
1, 1, 2, 3, 1, 4, 3, 3, 2, 7, 10, 3, 3, 2, 11, 3, 10, 3, 5, 4, 16, 21, 3, 10, 3, 5, 4, 22, 10, 21, 3, 10, 5, 5, 7, 29, 21, 10, 21, 3, 10, 5, 8, 7, 37, 10, 21, 10, 21, 3, 14, 5, 8, 11, 46, 55, 10, 21, 10, 21, 3, 14, 5, 8, 11, 56, 10, 55, 10, 21, 10, 21, 5, 14, 8, 12, 16, 67, 78, 10, 55, 10, 21, 10, 21, 5, 14, 8, 12, 16, 79, 21, 78, 10, 55, 10, 21, 10, 27, 5, 14, 8, 12, 22, 92
OFFSET
1,3
COMMENTS
Transpose of A286235.
EXAMPLE
The top left 12 X 12 corner of the array:
1, 1, 3, 3, 10, 3, 21, 10, 21, 10, 55, 10
2, 1, 3, 3, 10, 3, 21, 10, 21, 10, 55, 10
4, 2, 3, 3, 10, 3, 21, 10, 21, 10, 55, 10
7, 2, 5, 3, 10, 3, 21, 10, 21, 10, 55, 10
11, 4, 5, 5, 10, 3, 21, 10, 21, 10, 55, 10
16, 4, 5, 5, 14, 3, 21, 10, 21, 10, 55, 10
22, 7, 8, 5, 14, 5, 21, 10, 21, 10, 55, 10
29, 7, 8, 5, 14, 5, 27, 10, 21, 10, 55, 10
37, 11, 8, 8, 14, 5, 27, 14, 21, 10, 55, 10
46, 11, 12, 8, 14, 5, 27, 14, 27, 10, 55, 10
56, 16, 12, 8, 19, 5, 27, 14, 27, 14, 55, 10
67, 16, 12, 8, 19, 5, 27, 14, 27, 14, 65, 10
The first fifteen rows when viewed as a triangle:
1
1 2
3 1 4
3 3 2 7
10 3 3 2 11
3 10 3 5 4 16
21 3 10 3 5 4 22
10 21 3 10 5 5 7 29
21 10 21 3 10 5 8 7 37
10 21 10 21 3 14 5 8 11 46
55 10 21 10 21 3 14 5 8 11 56
10 55 10 21 10 21 5 14 8 12 16 67
78 10 55 10 21 10 21 5 14 8 12 16 79
21 78 10 55 10 21 10 27 5 14 8 12 22 92
36 21 78 10 55 10 21 10 27 5 19 8 17 22 106
MATHEMATICA
Map[(2 + (#1 + #2)^2 - #1 - 3 #2)/2 & @@ # & /@ Reverse@ # &, Table[{EulerPhi@ k, Floor[n/k]}, {n, 14}, {k, n}]] // Flatten (* Michael De Vlieger, May 06 2017 *)
PROG
(Scheme)
(define (A286234 n) (A286234bi (A002260 n) (A004736 n)))
(define (A286234bi row col) (let ((a (A000010 col)) (b (quotient (+ row col -1) col))) (* (/ 1 2) (+ (expt (+ a b) 2) (- a) (- (* 3 b)) 2))))
(Python)
from sympy import totient
def T(n, m): return ((n + m)**2 - n - 3*m + 2)/2
def t(n, k): return T(totient(k), int(n/k))
for n in range(1, 21): print [t(n, k) for k in range(1, n + 1)][::-1] # Indranil Ghosh, May 11 2017
CROSSREFS
Transpose: A286235.
Sequence in context: A125936 A243614 A200942 * A161621 A095701 A067992
KEYWORD
nonn,tabl
AUTHOR
Antti Karttunen, May 05 2017
STATUS
approved