A013708 -id:A013708 - cp's OEIS frontend

A004171 a(n) = 2^(2n+1).

2, 8, 32, 128, 512, 2048, 8192, 32768, 131072, 524288, 2097152, 8388608, 33554432, 134217728, 536870912, 2147483648, 8589934592, 34359738368, 137438953472, 549755813888, 2199023255552, 8796093022208, 35184372088832, 140737488355328, 562949953421312

Offset: 0

N. J. A. Sloane

Same as Pisot sequences E(2, 8), L(2, 8), P(2, 8), T(2, 8). See A008776 for definitions of Pisot sequences.
In the Chebyshev polynomial of degree 2n, a(n) is the coefficient of x^2n. - Benoit Cloitre, Mar 13 2002
1/2 - 1/8 + 1/32 - 1/128 + ... = 2/5. - Gary W. Adamson, Mar 03 2009
From Adi Dani, May 15 2011: (Start)
Number of ways of placing an even number of indistinguishable objects in n + 1 distinguishable boxes with at most 3 objects in box.
Number of compositions of even natural numbers into n + 1 parts less than or equal to 3 (0 is counted as part). (End)
Also the number of maximal cliques in the (n+1)-Sierpinski tetrahedron graph for n > 0. - Eric W. Weisstein, Dec 01 2017
Assuming the Collatz conjecture is true, any starting number eventually leads to a power of 2. A number in this sequence can never be the first power of 2 in a Collatz sequence except of course for the Collatz sequence starting with that number. For example, except for 8, 4, 2, 1, any Collatz sequence that includes 8 must also include 16 (e.g., 5, 16, 8, 4, 2, 1). - Alonso del Arte, Oct 01 2019
First differences of A020988, and thus the "wavelengths" of the local maxima in A020986. See the Brillhart and Morton link, pp. 855-856. - John Keith, Mar 04 2021

			G.f. = 2 + 8*x + 32*x^2 + 128*x^3 + 512*x^4 + 2048*x^5 + 8192*x^6 + 32768*x^7 + ...
From _Adi Dani_, May 15 2011: (Start)
a(1) = 8 because all compositions of even natural numbers into 2 parts less than or equal to 3 are:
  for 0: (0, 0)
  for 2: (0, 2), (2, 0), (1, 1)
  for 4: (1, 3), (3, 1), (2, 2)
  for 6: (3, 3).
a(2) = 32 because all compositions of even natural numbers into 3 parts less than or equal to 3 are:
  for 0: (0, 0, 0)
  for 2: (0, 0, 2), (0, 2, 0), (2, 0, 0), (0, 1, 1), (1, 0, 1) , (1, 1, 0)
  for 4: (0, 1, 3), (0, 3, 1), (1, 0, 3), (1, 3, 0), (3, 0, 1), (3, 1, 0), (0, 2, 2), (2, 0, 2), (2, 2, 0), (1, 1, 2), (1, 2, 1), (2, 1, 1)
  for 6: (0, 3, 3), (3, 0, 3), (3, 3, 0), (1, 2, 3), (1, 3, 2), (2, 1, 3), (2, 3, 1), (3, 1, 2), (3, 2, 1), (2, 2, 2)
  for 8: (2, 3, 3), (3, 2, 3), (3, 3, 2).
(End)

Adi Dani, Quasicompositions of natural numbers, Proceedings of III congress of mathematicians of Macedonia, Struga Macedonia 29 IX -2 X 2005 pages 225-238.

Vincenzo Librandi, Table of n, a(n) for n = 0..200
J. Brillhart and P. Morton, A case study in mathematical research: the Golay-Rudin-Shapiro sequence, Amer. Math. Monthly, 103 (1996) 854-869.
Ling Gao, Graph assembly for spider and tadpole graphs, Master's Thesis, Cal. State Poly. Univ. (2023).
Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets.
Tanya Khovanova, Recursive Sequences.
Mitchell Paukner, Lucy Pepin, Manda Riehl, and Jarred Wieser, Pattern Avoidance in Task-Precedence Posets, arXiv:1511.00080 [math.CO], 2015-2016.
Eric Weisstein's World of Mathematics, Maximal Clique.
Eric Weisstein's World of Mathematics, Sierpinski Tetrahedron Graph.
Index entries for linear recurrences with constant coefficients, signature (4).
Index to divisibility sequences.

Cf. A013708-A013729.
Absolute value of A009117. Essentially the same as A081294.
Cf. A132020, A164632. Equals A000980(n) + 2*A181765(n). Cf. A013776.

List([0..30],n->2^(2*n+1)); # Muniru A Asiru, Mar 12 2019

a004171 = (* 2) . a000302
a004171_list = iterate (* 4) 2  -- Reinhard Zumkeller, Jan 09 2013

[2^(2*n+1): n in [0..30]]; // Vincenzo Librandi, May 16 2011

seq(2^(2*n+1),n=0..24); # Nathaniel Johnston, Jun 25 2011

Table[2^(2 n + 1), {n, 0, 24}]
2^(2 Range[20] - 1) (* Eric W. Weisstein, Dec 01 2017 *)
LinearRecurrence[{4}, {2}, 20] (* Eric W. Weisstein, Dec 01 2017 *)
CoefficientList[Series[2/(1 - 4 x), {x, 0, 20}], x] (* Eric W. Weisstein, Dec 01 2017 *)

a(n)=2<<(2*n) \\ Charles R Greathouse IV, Apr 07 2012

a(n) = 2^(2*n+1) \\ Michel Marcus, Aug 12 2014

[2**(2*n+1) for n in range(0,25)] # Stefano Spezia, Jul 23 2025

((List.fill(20)(4: BigInt)).scanLeft(1: BigInt)( * )).map(2 * ) // _Alonso del Arte, Sep 12 2019

a(n) = 2*4^n.
a(n) = 4*a(n-1).
1 = 1/2 + Sum_{n >= 1} 3/a(n) = 3/6 + 3/8 + 3/32 + 3/128 + 3/512 + 3/2048 + ...; with partial sums: 1/2, 31/32, 127/128, 511/512, 2047/2048, ... - Gary W. Adamson, Jun 16 2003
From Philippe Deléham, Nov 23 2008: (Start)
a(n) = 2*A000302(n).
G.f.: 2/(1-4*x). (End)
a(n) = A081294(n+1) = A028403(n+1) - A000079(n+1) for n >= 1. a(n-1) = A028403(n) - A000079(n). - Jaroslav Krizek, Jul 27 2009
E.g.f.: 2*exp(4*x). - Ilya Gutkovskiy, Nov 01 2016
a(n) = A002063(n)/3 - A000302(n). - Zhandos Mambetaliyev, Nov 19 2016
a(n) = Sum_{k = 0..2*n} (-1)^(k+n)*binomial(4*n + 2, 2*k + 1); a(2*n) = Sum_{k = 0..2*n} binomial(4*n + 2, 2*k + 1) = A013776(n). - Peter Bala, Nov 25 2016
Product_{n>=0} (1 - 1/a(n)) = A132020. - Amiram Eldar, May 08 2023

A102518 a(n) = Sum_{k=0..n} binomial(n, k) * Sum_{j=0..k} binomial(3k, 3j).

Original entry on oeis.org

1, 3, 27, 243, 2187, 19683, 177147, 1594323, 14348907, 129140163, 1162261467, 10460353203, 94143178827, 847288609443, 7625597484987, 68630377364883, 617673396283947, 5559060566555523, 50031545098999707, 450283905890997363, 4052555153018976267, 36472996377170786403

Offset: 0

Paul Barry, Jan 13 2005

Binomial transform of A007613.
a(n+1) is the smallest number with a reciprocal with repeating decimal of period a(n). - Matthew Goers, Nov 09 2017
a(n) is the number of walks of 2n steps on the utility graph that start and end at the same vertex (excursions). A001019(n) is the number of 2n+1-step walks on the utility graph that end at one of the 3 adjacent vertices. A013708(n) is the number of 2n+2-step walks that end at one of the 2 remote vertices (at distance 2). The number of n-step walks on the utility (3-regular) graph, summed over all 3 types of final vertices, is 3^n. - R. J. Mathar, Nov 03 2020

Colin Barker, Table of n, a(n) for n = 0..1000
R. J. Mathar, Counting Walks on Finite Graphs, Section 4.
Index entries for linear recurrences with constant coefficients, signature (9).

Cf. A001019, A007613, A013708.

Join[{1},NestList[9#&,3,20]] (* Harvey P. Dale, Feb 03 2021 *)

Vec((1-6*x)/(1-9*x) + O(x^30)) \\ Colin Barker, Mar 17 2016

a(n) = 3^(2*n-1) + 2*0^k/3; a(n+1) = A013708(n).
G.f.: (1-6*x) / (1-9*x). - Colin Barker, Mar 17 2016
E.g.f.: (exp(9*x) + 2)/3. - Stefano Spezia, Jul 09 2024

A013729 a(n) = 24^(2*n + 1).

Original entry on oeis.org

24, 13824, 7962624, 4586471424, 2641807540224, 1521681143169024, 876488338465357824, 504857282956046106624, 290797794982682557415424, 167499529910025153071284224, 96479729228174488169059713024

Offset: 0

N. J. A. Sloane

Vincenzo Librandi, Table of n, a(n) for n = 0..100
Tanya Khovanova, Recursive Sequences
Index entries for linear recurrences with constant coefficients, signature (576).

Cf. A013708-A013728.

[24^(2*n+1): n in [0..15]]; // Vincenzo Librandi, May 25 2011

seq(24^(2*n+1),n=0..10); # Nathaniel Johnston, Jun 26 2011

24^(2*Range[0, 15]+1) (* or *)
NestList[576*# &, 24, 15] (* Paolo Xausa, Feb 21 2024 *)

a(n)=24^(2*n+1) \\ Charles R Greathouse IV, Jul 11 2016

From Philippe Deléham, Nov 28 2008: (Start)
a(n) = 576*a(n-1); a(0)=24.
G.f.: 24/(1-576*x).
a(n) = A013713(n)*A013708(n). (End)

A169634 a(n) = 3*7^n.

Original entry on oeis.org

3, 21, 147, 1029, 7203, 50421, 352947, 2470629, 17294403, 121060821, 847425747, 5931980229, 41523861603, 290667031221, 2034669218547, 14242684529829, 99698791708803, 697891541961621, 4885240793731347, 34196685556119429, 239376798892836003, 1675637592249852021

Offset: 0

Klaus Brockhaus, Apr 04 2010

Essentially first differences of A120741.
Binomial transform of A169604.
Second binomial transform of A005053 without initial term 1.
Inverse binomial transform of A103333 without initial term 1.
Second inverse binomial transform of A013708.
Except for first term 3, these are the integers that satisfy phi(n) = 4*n/7. - Michel Marcus, Jul 14 2015
Number of distinct quadratic residues (QR) over Z_7^n such that gcd(QR, 7^n) = 1 where n >= 1. - Param Mayurkumar Parekh, Feb 11 2023

Vincenzo Librandi, Table of n, a(n) for n = 0..300
Shalosh B. Ekhad and Doron Zeilberger, A Bijective Proof of Richard Stanley's Observation that the sum of the cubes of the n-th row of Stern's Diatomic array equals 3 times 7 to the power n-1, arXiv:2103.12852 [math.CO], 2021.
Richard P. Stanley, Some Linear Recurrences Motivated by Stern's Diatomic Array, arXiv:1901.04647 [math.CO], 2019. Also American Mathematical Monthly 127.2 (2020): 99-111.
Index entries for linear recurrences with constant coefficients, signature (7).

Cf. A120741, A169604 (3*6^n), A005053 (expand (1-2x)/(1-5x)), A103333 (expand (1-5x)/(1-8x)), A013708 (3^(2*n+1)), A007283 (3*2^n), A164346 (3*4^n).

Magma
```
[ 3*7^n: n in [0..19] ];
```

3*7^Range[0, 25] (* Paolo Xausa, Jan 17 2025 *)

a(n) = 7*a(n-1) for n > 0; a(0) = 3.

G.f.: 3/(1-7*x).

A223556 T(n,k)=Petersen graph (3,1) coloring a rectangular array: number of nXk 0..5 arrays where 0..5 label nodes of a graph with edges 0,1 0,3 3,5 3,4 1,2 1,4 4,5 2,0 2,5 and every array movement to a horizontal or antidiagonal neighbor moves along an edge of this graph, with the array starting at 0.

Original entry on oeis.org

1, 3, 6, 9, 27, 36, 27, 171, 243, 216, 81, 1089, 3249, 2187, 1296, 243, 6939, 44217, 61731, 19683, 7776, 729, 44217, 609309, 1795473, 1172889, 177147, 46656, 2187, 281763, 8410671, 53599905, 72906921, 22284891, 1594323, 279936, 6561, 1795473

Offset: 1

R. H. Hardin Mar 22 2013

Table starts
........1..........3.............9...............27...................81
........6.........27...........171.............1089.................6939
.......36........243..........3249............44217...............609309
......216.......2187.........61731..........1795473.............53599905
.....1296......19683.......1172889.........72906921...........4715559621
.....7776.....177147......22284891.......2960456193.........414863325945
....46656....1594323.....423412929.....120212193177.......36498667573629
...279936...14348907....8044845651....4881332621169.....3211064180380305
..1679616..129140163..152852067369..198211242377097...282501632829717621
.10077696.1162261467.2904189280011.8048559615522273.24853807982558115945

			Some solutions for n=3 k=4
..0..3..5..2....0..1..4..1....0..2..5..2....0..2..5..2....0..1..2..0
..5..3..0..1....0..1..0..3....1..2..5..2....5..2..1..4....2..0..1..2
..4..3..4..3....2..1..4..5....0..2..0..1....1..2..1..2....1..4..5..3

R. H. Hardin, Table of n, a(n) for n = 1..219

Column 1 is A000400(n-1)
Column 2 is A013708(n-1)
Column 3 = 9*19^(n-1) is row 8 of A223556 with T(2+,3) = A121057(8,1+)
Row 1 is A000244(n-1)

Empirical for column k:
k=1: a(n) = 6*a(n-1)
k=2: a(n) = 9*a(n-1)
k=3: a(n) = 19*a(n-1)
k=4: a(n) = 41*a(n-1) -16*a(n-2)
k=5: a(n) = 95*a(n-1) -626*a(n-2) +720*a(n-3) for n>4
k=6: [order 8] for n>9
k=7: [order 13] for n>15
Empirical for row n:
n=1: a(n) = 3*a(n-1)
n=2: a(n) = 7*a(n-1) -4*a(n-2) for n>3
n=3: a(n) = 17*a(n-1) -47*a(n-2) +41*a(n-3) -10*a(n-4) for n>6
n=4: [order 13] for n>16
n=5: [order 41] for n>45

A223331 T(n,k)=Rolling cube footprints: number of nXk 0..7 arrays starting with 0 where 0..7 label vertices of a cube and every array movement to a horizontal or antidiagonal neighbor moves along a corresponding cube edge.

Original entry on oeis.org

1, 3, 8, 9, 27, 64, 27, 189, 243, 512, 81, 1323, 3969, 2187, 4096, 243, 9261, 64827, 83349, 19683, 32768, 729, 64827, 1059723, 3176523, 1750329, 177147, 262144, 2187, 453789, 17324685, 121264857, 155649627, 36756909, 1594323, 2097152, 6561

Offset: 1

R. H. Hardin Mar 19 2013

Table starts
.........1..........3.............9................27....................81
.........8.........27...........189..............1323..................9261
........64........243..........3969.............64827...............1059723
.......512.......2187.........83349...........3176523.............121264857
......4096......19683.......1750329.........155649627...........13876429707
.....32768.....177147......36756909........7626831723.........1587890407761
....262144....1594323.....771895089......373714754427.......181703507374179
...2097152...14348907...16209796869....18312022966923.....20792470582897209
..16777216..129140163..340405734249...897289125379227...2379298227030964827
.134217728.1162261467.7148520419229.43967167143582123.272264906211251105313
Horizontal or vertical instead of horizontal or antidiagonal gives A222444

			Some solutions for n=3 k=4
..0..4..5..1....0..4..0..1....0..4..6..4....0..2..0..4....0..4..6..4
..5..4..0..1....5..1..5..1....0..2..0..2....6..2..6..4....6..2..6..7
..6..2..3..1....5..7..3..2....3..2..3..1....6..4..0..4....0..2..6..7
Vertex neighbors:
0 -> 1 2 4
1 -> 0 3 5
2 -> 0 3 6
3 -> 1 2 7
4 -> 0 5 6
5 -> 1 4 7
6 -> 2 4 7
7 -> 3 5 6

R. H. Hardin, Table of n, a(n) for n = 1..199

Column 1 is A001018(n-1)
Column 2 is A013708(n-1)
Column 3 is 9*21^(n-1)
Column 4 is 27*49^(n-1)
Row 1 is A000244(n-1)
Row 2 is 27*7^(n-2) for n>1

Empirical for column k:
k=1: a(n) = 8*a(n-1)
k=2: a(n) = 9*a(n-1)
k=3: a(n) = 21*a(n-1)
k=4: a(n) = 49*a(n-1)
k=5: a(n) = 117*a(n-1) -294*a(n-2)
k=6: a(n) = 282*a(n-1) -3969*a(n-2) +9604*a(n-3)
k=7: a(n) = 692*a(n-1) -43569*a(n-2) +847042*a(n-3) -6303164*a(n-4) +15731352*a(n-5)
Empirical for row n:
n=1: a(n) = 3*a(n-1)
n=2: a(n) = 7*a(n-1) for n>2
n=3: a(n) = 18*a(n-1) -27*a(n-2) for n>4
n=4: a(n) = 48*a(n-1) -402*a(n-2) +1064*a(n-3) -789*a(n-4) for n>7
n=5: [order 9] for n>13
n=6: [order 20] for n>25
n=7: [order 51] for n>57

A223480 T(n,k)=Rolling icosahedron face footprints: number of nXk 0..19 arrays starting with 0 where 0..19 label faces of an icosahedron and every array movement to a horizontal or antidiagonal neighbor moves across an icosahedral edge.

Original entry on oeis.org

1, 3, 20, 9, 27, 400, 27, 135, 243, 8000, 81, 675, 2025, 2187, 160000, 243, 3375, 16875, 30375, 19683, 3200000, 729, 16875, 147825, 421875, 455625, 177147, 64000000, 2187, 84375, 1296675, 6526575, 10546875, 6834375, 1594323, 1280000000, 6561, 421875

Offset: 1

R. H. Hardin Mar 20 2013

Table starts
..........1........3..........9...........27.............81..............243
.........20.......27........135..........675...........3375............16875
........400......243.......2025........16875.........147825..........1296675
.......8000.....2187......30375.......421875........6526575........101331675
.....160000....19683.....455625.....10546875......288507825.......7939566675
....3200000...177147....6834375....263671875....12755926575.....622332801675
...64000000..1594323..102515625...6591796875...563999907825...48783753036675
.1280000000.14348907.1537734375.164794921875.24937217326575.3824122400271675

			Some solutions for n=3 k=4
..0..1..6.10....0..1..4..1....0..1..0..1....0..2..8.13....0..2..8..9
..6..1..6..1....6..1..4..3....4..1..0..5....0..2..8..2....8..9..8..9
..4..1..4..3....4.17..4.17....0..5..9..5....8..2..3..4....8..2..8..9
Face neighbors:
0 -> 1 2 5
1 -> 0 4 6
2 -> 0 3 8
3 -> 2 4 16
4 -> 3 1 17
5 -> 0 7 9
6 -> 1 7 10
7 -> 6 5 11
8 -> 2 9 13
9 -> 8 5 14
10 -> 6 12 17
11 -> 7 12 14
12 -> 11 10 19
13 -> 8 15 16
14 -> 9 11 15
15 -> 14 13 19
16 -> 3 13 18
17 -> 4 10 18
18 -> 16 17 19
19 -> 15 18 12

R. H. Hardin, Table of n, a(n) for n = 1..160

Column 1 is A009964(n-1)
Column 2 is A013708(n-1)
Column 3 is 9*15^(n-1)
Column 4 is 27*25^(n-1)
Row 1 is A000244(n-1)
Row 2 is 27*5^(n-2) for n>1

Empirical for column k:
k=1: a(n) = 20*a(n-1)
k=2: a(n) = 9*a(n-1)
k=3: a(n) = 15*a(n-1)
k=4: a(n) = 25*a(n-1)
k=5: a(n) = 51*a(n-1) -300*a(n-2)
k=6: a(n) = 101*a(n-1) -1900*a(n-2) +10000*a(n-3)
k=7: a(n) = 227*a(n-1) -14764*a(n-2) +411840*a(n-3) -5347200*a(n-4) +29600000*a(n-5) -48000000*a(n-6)
Empirical for row n:
n=1: a(n) = 3*a(n-1)
n=2: a(n) = 5*a(n-1) for n>2
n=3: a(n) = 9*a(n-1) -2*a(n-2) for n>4
n=4: a(n) = 17*a(n-1) -16*a(n-2) -76*a(n-3) +64*a(n-4) for n>7
n=5: a(n) = 33*a(n-1) -86*a(n-2) -1564*a(n-3) +7040*a(n-4) -6480*a(n-5) -5088*a(n-6) +5824*a(n-7) -512*a(n-8) for n>13
n=6: [order 20] for n>25

A013715 a(n) = 10^(2*n+1).

Original entry on oeis.org

10, 1000, 100000, 10000000, 1000000000, 100000000000, 10000000000000, 1000000000000000, 100000000000000000, 10000000000000000000, 1000000000000000000000, 100000000000000000000000, 10000000000000000000000000, 1000000000000000000000000000, 100000000000000000000000000000

Offset: 0

N. J. A. Sloane

Bisection of A011557 (powers of 10). - Michel Marcus, Jan 17 2016

Vincenzo Librandi, Table of n, a(n) for n = 0..100
Tanya Khovanova, Recursive Sequences
Index entries for linear recurrences with constant coefficients, signature (100).

Cf. A013708-A013714, A013716-A013729, A011557.

Cf. A005408, A098608, A013747.

[10^(2*n+1): n in [0..20]]; // Vincenzo Librandi, Jun 26 2011

seq(10^(2*n+1),n=0..11); # Nathaniel Johnston, Jun 25 2011

10^(2 Range[0, 15] + 1) (* Wesley Ivan Hurt, Jan 17 2016 *)

a(n) = 10^(2*n+1); \\ Michel Marcus, Jan 17 2016

Vec(10/(1-100*x) + O(x^100)) \\ Altug Alkan, Jan 17 2016

From Philippe Deléham, Nov 25 2008: (Start)
G.f.: 10/(1-100*x).
a(n) = 100*a(n-1), n>0; a(0)=10. (End)
From Elmo R. Oliveira, Aug 26 2024 (Start)
E.g.f.: 10*exp(100*x).
a(n) = 10*A098608(n) = A011557(A005408(n)) = A013747(n)/10^(n+1). (End)

A013716 a(n) = 11^(2*n + 1).

Original entry on oeis.org

11, 1331, 161051, 19487171, 2357947691, 285311670611, 34522712143931, 4177248169415651, 505447028499293771, 61159090448414546291, 7400249944258160101211, 895430243255237372246531

Offset: 0

N. J. A. Sloane

Vincenzo Librandi, Table of n, a(n) for n = 0..200
Tanya Khovanova, Recursive Sequences
Index entries for linear recurrences with constant coefficients, signature (121).

Bisection of A001020 (11^n).

Cf. A013708-A013715, A013717-A013729.

[11^(2*n+1): n in [0..15]]; // Vincenzo Librandi, Jun 26 2011

seq(11^(2*n+1),n=0..11); # Nathaniel Johnston, Jun 25 2011

11^(2*Range[0,20]+1) (* or *) NestList[121#&,11,20] (* Harvey P. Dale, Jun 21 2024 *)

a(n)=11^(2*n+1) \\ Charles R Greathouse IV, Jul 11 2016

From Philippe Deléham, Nov 25 2008: (Start)
a(n) = 121*a(n-1), a(0)=11.
G.f.: 11/(1-121*x). (End)

A013718 a(n) = 13^(2*n + 1).

Original entry on oeis.org

13, 2197, 371293, 62748517, 10604499373, 1792160394037, 302875106592253, 51185893014090757, 8650415919381337933, 1461920290375446110677, 247064529073450392704413, 41753905413413116367045797

Offset: 0

N. J. A. Sloane

Vincenzo Librandi, Table of n, a(n) for n = 0..200
Tanya Khovanova, Recursive Sequences
Index entries for linear recurrences with constant coefficients, signature (169).

Bisection of A001022 (12^n).

Cf. A013708-A013717, A013719-A013729.

[13^(2*n+1): n in [0..15]]; // Vincenzo Librandi, Jun 26 2011

seq(13^(2*n+1),n=0..11); # Nathaniel Johnston, Jun 25 2011

a(n)=13^(2*n+1) \\ Charles R Greathouse IV, Jul 11 2016

From Philippe Deléham, Nov 25 2008: (Start)
a(n) = 169*a(n-1); a(0)=13.
G.f.: 13/(1-169*x). (End)

cp's OEIS Frontend

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