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A291578 The arithmetic function uhat(n,7,7). 0
1, 1, 1, 1, 1, 1, -5, 1, 1, 1, 1, 1, 1, -5, 1, 1, 1, 1, 1, 1, -5, 1, 1, 1, 1, 1, 1, -5, 1, 1, 1, 1, 1, 1, -5, 1, 1, 1, 1, 1, 1, -5, 1, 1, 1, 1, 1, 1, -5, 1, 1, 1, 1, 1, 1, -5, 1, 1, 1, 1, 1, 1, -5, 1, 1, 1, 1, 1, 1, -5 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

LINKS

Table of n, a(n) for n=1..70.

Bela Bajnok, Additive Combinatorics: A Menu of Research Problems, arXiv:1705.07444 [math.NT], May 2017. See Table in Section 1.6.4.

MATHEMATICA

delta[r_, k_, d_] := If[r < k, (k - r)*r - (d - 1), If[k < r && r < d, (d - r)*(r - k) - (d - 1), If[k == r && r == d, d - 1, 0]]] uhat[n_, m_, h_] := (dx = Divisors[n]; dmin = n; For[i = 1, i ≤ Length[dx], i++, d = dx[[i]]; k = m - d*Ceiling[m/d] + d; r = h - d*Ceiling[h/d] + d; If[h ≤ Min[k, d - 1], dmin = Min[dmin, n, (h*Ceiling[m/d] - h + 1)*d, h*m - h*h + 1], dmin = Min[dmin, n, h*m - h*h + 1 - delta[r, k, d]]]]; dmin) Table[uhat[n, 7, 7], {n, 1, 70}]

CROSSREFS

Cf. A289435, A289436, A289437, A289438, A289439, A289440, A289441.

Sequence in context: A319099 A098087 A257099 * A165485 A179947 A046623

Adjacent sequences:  A291575 A291576 A291577 * A291579 A291580 A291581

KEYWORD

sign

AUTHOR

Robert Price, Aug 26 2017

STATUS

approved

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Last modified February 16 21:59 EST 2019. Contains 320200 sequences. (Running on oeis4.)