A016197
a(n) = 12^n - 11^n.
Original entry on oeis.org
0, 1, 23, 397, 6095, 87781, 1214423, 16344637, 215622815, 2801832661, 35979939623, 457696700077, 5777672071535, 72470493235141, 904168630965623, 11229773405170717, 138934529031464255, 1713164078241143221
Offset: 0
Cf. k^n-(k-1)^n:
A000225 (k=2),
A001047 (k=3),
A005061 (k=4),
A005060 (k=5),
A005062 (k=6),
A016169 (k=7),
A016177 (k=8),
A016185 (k=9),
A016189 (k=10),
A016195 (k=11), this sequence (k=12).
A327316
Triangular array read by rows: row n shows the coefficients of this polynomial of degree n: p(x,n) = ((x+r)^n - (x+s)^n)/(r - s), where r = 3 and s = 2.
Original entry on oeis.org
1, 5, 2, 19, 15, 3, 65, 76, 30, 4, 211, 325, 190, 50, 5, 665, 1266, 975, 380, 75, 6, 2059, 4655, 4431, 2275, 665, 105, 7, 6305, 16472, 18620, 11816, 4550, 1064, 140, 8, 19171, 56745, 74124, 55860, 26586, 8190, 1596, 180, 9, 58025, 191710, 283725, 247080
Offset: 1
First seven rows:
1
5 2
19 15 3
65 76 30 4
211 325 190 50 5
665 1266 975 380 75 6
2059 4655 4431 2275 665 105 7
-
f[x_, n_] := ((x + r)^n - (x + s)^n)/(r - s);
r = 3; s = 2;
Column[Table[Expand[f[x, n]], {n, 1, 5}]]
c[x_, n_] := CoefficientList[Expand[f[x, n]], x]
TableForm[Table[c[x, n], {n, 1, 10}]] (* A327316 array *)
Flatten[Table[c[x, n], {n, 1, 12}]] (* A327316 sequence *)
A343237
Triangle T obtained from the array A(n, k) = (k+1)^(n+1) - k^(n+1), n, k >= 0, by reading antidiagonals upwards.
Original entry on oeis.org
1, 1, 1, 1, 3, 1, 1, 7, 5, 1, 1, 15, 19, 7, 1, 1, 31, 65, 37, 9, 1, 1, 63, 211, 175, 61, 11, 1, 1, 127, 665, 781, 369, 91, 13, 1, 1, 255, 2059, 3367, 2101, 671, 127, 15, 1, 1, 511, 6305, 14197, 11529, 4651, 1105, 169, 17, 1
Offset: 0
The array A begins:
n\k 0 1 2 3 4 5 6 7 8 9 ...
-------------------------------------------------------------
0: 1 1 1 1 1 1 1 1 1 1 ...
1: 1 3 5 7 9 11 13 15 17 19 ...
2: 1 7 19 37 61 91 127 169 217 271 ...
3: 1 15 65 175 369 671 1105 1695 2465 3439 ...
4: 1 31 211 781 2101 4651 9031 15961 26281 40951 ...
5: 1 63 665 3367 11529 31031 70993 144495 269297 468559 ...
...
The triangle T begins:
n\m 0 1 2 3 4 5 6 7 8 9 10 ...
-------------------------------------------------------------
0: 1
1: 1 1
2: 1 3 1
3: 1 7 5 1
4: 1 15 19 7 1
5: 1 31 65 37 9 1
6: 1 63 211 175 61 11 1
7: 1 127 665 781 369 91 13 1
8: 1 255 2059 3367 2101 671 127 15 1
9: 1 511 6305 14197 11529 4651 1105 169 17 1
10: 1 1023 19171 58975 61741 31031 9031 1695 217 19 1
...
Combinatorial interpretation (cf. A005061 by _Enrique Navarrete_)
The three digits numbers with digits from K ={1, 2, 3, 4} having at least one 4 are:
j=1 (one 4): 114, 141, 411; 224, 242, 422; 334, 343, 433; 124, 214, 142, 241, 412, 421; 134, 314, 143, 341, 413, 431; 234, 243, 423. That is, 3*3 + 3!*3 = 27 = binomial(3, 1)*(4-1)^(3-1) = 3*3^2;
j=2 (twice 4): 144, 414, 441; 244, 424, 442; 344, 434, 443; 3*3 = 9 = binomial(3, 2)*(4-1)^(3-2) = 3*3;
j=3 (thrice 4) 444; 1 = binomial(3, 3)*(4-1)^(3-3).
Together: 27 + 9 + 1 = 37 = A(2, 3) = T(5, 3).
Row sequences of array A (nexus numbers):
A000012,
A005408,
A003215,
A005917(k+1),
A022521,
A022522,
A022523,
A022524,
A022525,
A022526,
A022527,
A022528.
Column sequences of array A:
A000012,
A000225(n+1),
A001047(n+1),
A005061(n+1),
A005060(n+1),
A005062(n+1),
A016169(n+1),
A016177(n+1),
A016185(n+1),
A016189(n+1),
A016195(n+1),
A016197(n+1).
-
egf := exp(exp(x)*y + x)*(exp(x)*y - y + 1): ser := series(egf, x, 12):
cx := n -> series(n!*coeff(ser, x, n), y, 12):
Arow := n -> seq(k!*coeff(cx(n), y, k), k=0..9):
for n from 0 to 5 do Arow(n) od; # Peter Luschny, May 10 2021
-
A[n_, k_] := (k + 1)^(n + 1) - k^(n + 1); Table[A[n - k, k], {n, 0, 9}, {k, 0, n}] // Flatten (* Amiram Eldar, May 10 2021 *)
A020782
Expansion of g.f. 1/((1-7*x)*(1-8*x)*(1-9*x)).
Original entry on oeis.org
1, 24, 385, 5160, 62401, 706104, 7628545, 79669320, 810888001, 8089258584, 79415935105, 769621605480, 7379461252801, 70134974713464, 661651583000065, 6203106293141640, 57847125937972801, 537010118353326744, 4965807358070423425, 45765395460943045800, 420553385321258904001
Offset: 0
-
CoefficientList[Series[1/((1-7x)(1-8x)(1-9x)),{x,0,20}],x] (* or *) LinearRecurrence[{24,-191,504},{1,24,385},20] (* Harvey P. Dale, Aug 20 2013 *)
A248340
a(n) = 10^n - 5^n.
Original entry on oeis.org
0, 5, 75, 875, 9375, 96875, 984375, 9921875, 99609375, 998046875, 9990234375, 99951171875, 999755859375, 9998779296875, 99993896484375, 999969482421875, 9999847412109375, 99999237060546875, 999996185302734375, 9999980926513671875
Offset: 0
-
[10^n-5^n: n in [0..30]];
-
Table[10^n - 5^n, {n,0,30}]
CoefficientList[Series[5 x/((1-5 x)(1-10 x)), {x, 0, 30}], x]
-
def A248340(n): return pow(10,n) - pow(5,n)
print([A248340(n) for n in range(41)]) # G. C. Greubel, Nov 13 2024
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