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A268512 Triangle of coefficients c(n,i), 1<=i<=n, such that for each n>=2, c(n,i) are setwise coprime; and for all primes p>2n-1, the sum of (-1)^i*c(n,i)*binomial(i*p,p) is divisible by p^(2n-1). 5
1, 2, 1, 12, 9, 2, 60, 54, 20, 3, 840, 840, 400, 105, 12, 2520, 2700, 1500, 525, 108, 10, 27720, 31185, 19250, 8085, 2268, 385, 30, 360360, 420420, 280280, 133770, 45864, 10780, 1560, 105, 720720, 864864, 611520, 321048, 127008, 36960, 7488, 945, 56, 12252240, 15036840, 11138400, 6297480, 2776032, 942480 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..51.

R. R. Aidagulov, M. A. Alekseyev. On p-adic approximation of sums of binomial coefficients. Journal of Mathematical Sciences 233:5 (2018), 626-634. doi:10.1007/s10958-018-3948-0; also arXiv, arXiv:1602.02632 [math.NT], 2016-2018.

FORMULA

c(n,i) = A003418(2*(n-1))*binomial(2*n-1,n-i)*(2*i-1)/i/binomial(2*n-1,n).

EXAMPLE

n=1: 1

n=2: 2, 1

n=3: 12, 9, 2

n=4: 60, 54, 20, 3

n=5: 840, 840, 400, 105, 12

...

For all primes p>3, p^3 divides 2 - binomial(2*p,p) (cf. A087754).

For all primes p>5, p^5 divides 12 - 9*binomial(2*p,p) + 2*binomial(3*p,p) (cf. A268589).

For all primes p>7, p^7 divides 60 - 54*binomial(2*p,p) + 20*binomial(3*p,p) - 3*binomial(4*p,p) (cf. A268590).

MATHEMATICA

a3418[n_] := LCM @@ Range[n];

c[1, 1] = 1; c[n_, i_] := a3418[2(n-1)] Binomial[2n-1, n-i] ((2i-1)/i/ Binomial[2n-1, n]);

Table[c[n, i], {n, 1, 10}, {i, 1, n}] // Flatten (* Jean-Fran├žois Alcover, Dec 04 2018 *)

PROG

(PARI) { A268512(n, i) = lcm(vector(2*(n-1), i, i)) * binomial(2*n-1, n-i) * (2*i-1) / i / binomial(2*n-1, n) }

CROSSREFS

Cf. A099996 (first column), A068550 (diagonal), A087754, A268589, A268590, A254593.

Sequence in context: A130559 A135256 A090586 * A217109 A297967 A199930

Adjacent sequences:  A268509 A268510 A268511 * A268513 A268514 A268515

KEYWORD

nonn,tabl

AUTHOR

Max Alekseyev, Feb 06 2016

STATUS

approved

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Last modified July 6 23:56 EDT 2020. Contains 335484 sequences. (Running on oeis4.)