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A296307
Array read by upwards antidiagonals: f(n,k) = (n+1)*ceiling(n/(k-1)) - 1.
1
1, 5, 1, 11, 2, 1, 19, 7, 2, 1, 29, 9, 3, 2, 1, 41, 17, 9, 3, 2, 1, 55, 20, 11, 4, 3, 2, 1, 71, 31, 13, 11, 4, 3, 2, 1, 89, 35, 23, 13, 5, 4, 3, 2, 1, 109, 49, 26, 15, 13, 5, 4, 3, 2, 1, 131, 54, 29, 17, 15, 6, 5, 4, 3, 2, 1, 155, 71, 43, 29, 17, 15, 6, 5, 4, 3
OFFSET
1,2
COMMENTS
f(n,k) = (n+1)*ceiling(n/(k-1))-1 is the Frobenius number F(n+1,n+2,...,n+k), k>1. This formula is derived in "Frobenius number for a set of successive numbers".
f(n,k) is the greatest number which is not a linear combination of n+1,n+2,...,n+k with nonnegative coefficients.
Example: f(2,3) = 5 because 6=2*3, 7=3+4, 8=2*4, 9=3*3, 10=2*3+4 and so on.
Special sequences: f(n,2) = A028387(n), f(n,3) = A079326(n+1), f(n,4) = A138984(n), f(n,5) = A138985(n), f(n,6) = A138986(n), f(n,7) = A138987(n), f(n,8) = A138988(n).
f(n,k) is a generalization of these sequences.
EXAMPLE
Example:
f(n,2) f(n,3) f(n,4)
a(1)= 1 a(3)=1 a(6) =1
a(2)= 5 a(5)=2 a(9) =2
a(4)=11 a(8)=7 a(13)=3
More terms in "Table of Frobenius numbers".
KEYWORD
nonn,tabl
AUTHOR
Gerhard Kirchner, Dec 10 2017
STATUS
approved