A291521 - OEIS

A291521

The arithmetic function uhat(n,4,6).

-11, -12, -11, -12, -11, -12, -11, -12, -11, -12, -11, -12, -13, -14, -15, -16, -17, -18, -19, -20, -21, -22, -23, -24, -25, -26, -27, -28, -29, -30, -31, -32, -33, -34, -35, -36, -37, -38, -39, -40, -41, -42, -43, -44, -45, -46, -47, -48, -49, -50, -51, -52, -53, -54, -55, -56, -57, -58, -59, -60, -61, -62, -63, -64, -65, -66, -67, -68, -69, -70

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OFFSET

1,1

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, 4, 6], {n, 1, 70}]

CROSSREFS

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

Sequence in context: A264811 A352389 A020510 * A324309 A270036 A178405

Adjacent sequences: A291518 A291519 A291520 * A291522 A291523 A291524

KEYWORD

sign

AUTHOR

Robert Price, Aug 25 2017

STATUS

approved