A054880
a(n) = 3*(9^n - 1)/4.
Original entry on oeis.org
0, 6, 60, 546, 4920, 44286, 398580, 3587226, 32285040, 290565366, 2615088300, 23535794706, 211822152360, 1906399371246, 17157594341220, 154418349070986, 1389765141638880, 12507886274749926, 112570976472749340, 1013138788254744066, 9118249094292696600, 82064241848634269406, 738578176637708424660
Offset: 0
Paolo Dominici (pl.dm(AT)libero.it), May 23 2000
- G. C. Greubel, Table of n, a(n) for n = 0..1000
- G. Benkart and D. Moon, A Schur-Weyl Duality Approach to Walking on Cubes, arXiv preprint arXiv:1409.8154 [math.RT], 2014 and Ann. Combin. 20 (3) (2016) 397-417
- R. J. Mathar, Counting Walks on Finite Graphs, Nov 2020, Section 5.
- Index entries for linear recurrences with constant coefficients, signature (10,-9).
-
List([0..30], n-> 3*(9^n -1)/4); # G. C. Greubel, Jul 14 2019
-
[3*(9^n -1)/4: n in [0..30]]; // G. C. Greubel, Jul 14 2019
-
Table[(2 n + 1)! Coefficient[Series[Sinh[x]^3, {x, 0, 2 n + 1}],
x^(2 n + 1)], {n, 0, 30}] (* Geoffrey Critzer, May 23 2013 *)
LinearRecurrence[{10,-9},{0,6},30] (* Harvey P. Dale, Sep 17 2024 *)
-
vector(30, n, n--; 3*(9^n -1)/4) \\ G. C. Greubel, Jul 14 2019
-
[3*(9^n -1)/4 for n in (0..30)] # G. C. Greubel, Jul 14 2019
A125857
Numbers whose base-9 representation is 22222222.......2.
Original entry on oeis.org
0, 2, 20, 182, 1640, 14762, 132860, 1195742, 10761680, 96855122, 871696100, 7845264902, 70607384120, 635466457082, 5719198113740, 51472783023662, 463255047212960, 4169295424916642, 37523658824249780, 337712929418248022
Offset: 1
G.f. = 2*x^2 + 20*x^3 + 182*x^4 + 1640*x^5 + 14762*x^6 + 132860*x^7 + ... - _Michael Somos_, Jul 28 2020
- G. Benkart, D. Moon, A Schur-Weyl Duality Approach to Walking on Cubes, arXiv preprint arXiv:1409.8154 [math.RT], 2014 and Ann. Combin. 20 (3) (2016) 397-417
- E. Estrada and J. A. de la Pena, From Integer Sequences to Block Designs via Counting Walks in Graphs, arXiv preprint arXiv:1302.1176 [math.CO], 2013. - From _N. J. A. Sloane_, Feb 28 2013
- E. Estrada and J. A. de la Pena, Integer sequences from walks in graphs, Notes on Number Theory and Discrete Mathematics, Vol. 19, 2013, No. 3, 78-84.
- R. J. Mathar, Counting Walks on Finite Graphs, Nov 2020, Section 5.
- Vladimir Pletser, Congruence conditions on the number of terms in sums of consecutive squared integers equal to squared integers, arXiv:1409.7969 [math.NT], 2014.
- Index entries for linear recurrences with constant coefficients, signature (10,-9).
-
seq((9^n-1)*2/8, n=0..19);
-
FromDigits[#, 9]&/@Table[PadRight[{2}, n, 2], {n, 0, 20}] (* Harvey P. Dale, Feb 02 2011 *)
Table[(9^(n - 1) - 1)*2/8, {n, 20}] (* Wesley Ivan Hurt, Mar 29 2014 *)
-
Vec(2*x^2/((x-1)*(9*x-1)) + O(x^100)) \\ Colin Barker, Sep 30 2014
-
{a(n) = (9^(n-1) - 1)/4}; /* Michael Somos, Jul 02 2017 */
A210461
Cipolla pseudoprimes to base 3: (9^p-1)/8 for any odd prime p.
Original entry on oeis.org
91, 7381, 597871, 3922632451, 317733228541, 2084647712458321, 168856464709124011, 1107867264956562636991, 588766087155780604365200461, 47690053059618228953581237351, 25344449488056571213320166359119221, 166284933091139163730593611482181209801
Offset: 1
Bruno Berselli, Jan 22 2013 - proposed by Umberto Cerruti (Department of Mathematics "Giuseppe Peano", University of Turin, Italy)
91 is in the sequence because 91=((3^3-1)/2)*((3^3+1)/4), even if p=3 divides 3*(3^2-1), and 3^90 = (91*8+1)^15 == 1 (mod 91).
7381 is in the sequence because 7381=((3^5-1)/2)*((3^5+1)/4) and 3^7380 = (7381*472400+1)^369 == 1 (mod 7381).
- Michele Cipolla, Sui numeri composti P che verificano la congruenza di Fermat a^(P-1) = 1 (mod P), Annali di Matematica 9 (1904), p. 139-160.
-
a210461 = (`div` 8) . (subtract 1) . (9 ^) . a065091
-- Reinhard Zumkeller, Jan 22 2013
-
[(9^NthPrime(n)-1)/8: n in [2..12]];
-
P:=proc(q)local n;
for n from 2 to q do print((9^ithprime(n)-1)/8);
od; end: P(100); # Paolo P. Lava, Oct 11 2013
-
(9^# - 1)/8 & /@ Prime[Range[2, 12]]
-
Prime(n) := block(if n = 1 then return(2), return(next_prime(Prime(n-1))))$
makelist((9^Prime(n)-1)/8, n, 2, 12);
A218728
a(n) = (25^n - 1)/24.
Original entry on oeis.org
0, 1, 26, 651, 16276, 406901, 10172526, 254313151, 6357828776, 158945719401, 3973642985026, 99341074625651, 2483526865641276, 62088171641031901, 1552204291025797526, 38805107275644938151, 970127681891123453776, 24253192047278086344401, 606329801181952158610026
Offset: 0
Cf. similar sequences of the form (k^n-1)/(k-1):
A000225,
A003462,
A002450,
A003463,
A003464,
A023000,
A023001,
A002452,
A002275,
A016123,
A016125,
A091030,
A135519,
A135518,
A131865,
A091045,
A218721,
A218722,
A064108,
A218724-
A218734,
A132469,
A218736-
A218753,
A133853,
A094028,
A218723.
-
[n le 2 select n-1 else 26*Self(n-1)-25*Self(n-2): n in [1..20]]; // Vincenzo Librandi, Nov 07 2012
-
LinearRecurrence[{26, -25}, {0, 1}, 30] (* Vincenzo Librandi, Nov 07 2012 *)
(25^Range[0,20]-1)/24 (* Harvey P. Dale, Aug 23 2020 *)
-
A218728(n):=(25^n-1)/24$
makelist(A218728(n),n,0,30); /* Martin Ettl, Nov 07 2012 */
-
A218728(n)=25^n\24
A218743
a(n) = (40^n - 1)/39.
Original entry on oeis.org
0, 1, 41, 1641, 65641, 2625641, 105025641, 4201025641, 168041025641, 6721641025641, 268865641025641, 10754625641025641, 430185025641025641, 17207401025641025641, 688296041025641025641, 27531841641025641025641, 1101273665641025641025641, 44050946625641025641025641
Offset: 0
Cf. similar sequences of the form (k^n-1)/(k-1):
A000225,
A003462,
A002450,
A003463,
A003464,
A023000,
A023001,
A002452,
A002275,
A016123,
A016125,
A091030,
A135519,
A135518,
A131865,
A091045,
A218721,
A218722,
A064108,
A218724-
A218734,
A132469,
A218736-
A218753,
A133853,
A094028,
A218723.
-
[n le 2 select n-1 else 41*Self(n-1) - 40*Self(n-2): n in [1..20]]; // Vincenzo Librandi, Nov 07 2012
-
LinearRecurrence[{41, -40}, {0, 1}, 30] (* Vincenzo Librandi, Nov 07 2012 *)
-
A218743(n):=floor(40^n/39)$ makelist(A218743(n),n,0,30); /* Martin Ettl, Nov 05 2012 */
-
a(n)=40^n\39
A269025
a(n) = Sum_{k = 0..n} 60^k.
Original entry on oeis.org
1, 61, 3661, 219661, 13179661, 790779661, 47446779661, 2846806779661, 170808406779661, 10248504406779661, 614910264406779661, 36894615864406779661, 2213676951864406779661, 132820617111864406779661, 7969237026711864406779661, 478154221602711864406779661
Offset: 0
Cf. similar sequences of the form (k^n-1)/(k-1):
A000225 (k=2),
A003462 (k=3),
A002450 (k=4),
A003463 (k=5),
A003464 (k=6),
A023000 (k=7),
A023001 (k=8),
A002452 (k=9),
A002275 (k=10),
A016123 (k=11),
A016125 (k=12),
A091030 (k=13),
A135519 (k=14),
A135518 (k=15),
A131865 (k=16),
A091045 (k=17),
A218721 (k=18),
A218722 (k=19),
A064108 (k=20),
A218724-
A218734 (k=21..31),
A132469 (k=32),
A218736-
A218753 (k=33..50), this sequence (k=60),
A133853 (k=64),
A094028 (k=100),
A218723 (k=256),
A261544 (k=1000).
-
Table[Sum[60^k, {k, 0, n}], {n, 0, 15}]
Table[(60^(n + 1) - 1)/59, {n, 0, 15}]
LinearRecurrence[{61, -60}, {1, 61}, 15]
-
a(n)=60^n + 60^n\59 \\ Charles R Greathouse IV, Jul 26 2016
A291560
E.g.f. A(x,k) satisfies: sin(A(x,k)) = k * sin(x).
Original entry on oeis.org
1, -1, 1, 1, -10, 9, -1, 91, -315, 225, 1, -820, 8694, -18900, 11025, -1, 7381, -224730, 1143450, -1819125, 893025, 1, -66430, 5684679, -61647300, 203378175, -255405150, 108056025, -1, 597871, -142714845, 3162834675, -19494349875, 47377655325, -49165491375, 18261468225, 1, -5380840, 3573251964, -158546770200, 1734021238950, -7311738634200, 14041664336700, -12417798393000, 4108830350625, -1, 48427561, -89379726660, 7858123038900, -148224512094750, 1025176095093150, -3257761647640500, 5167045911327300, -3981456609755625, 1187451971330625
Offset: 1
This triangle of coefficients T(n,r) in e.g.f. A(x,k) begins:
[1],
[-1, 1],
[1, -10, 9],
[-1, 91, -315, 225],
[1, -820, 8694, -18900, 11025],
[-1, 7381, -224730, 1143450, -1819125, 893025],
[1, -66430, 5684679, -61647300, 203378175, -255405150, 108056025],
[-1, 597871, -142714845, 3162834675, -19494349875, 47377655325, -49165491375, 18261468225],
[1, -5380840, 3573251964, -158546770200, 1734021238950, -7311738634200, 14041664336700, -12417798393000, 4108830350625],
[-1, 48427561, -89379726660, 7858123038900, -148224512094750, 1025176095093150, -3257761647640500, 5167045911327300, -3981456609755625, 1187451971330625],
[1, -435848050, 2234929014549, -387282522072600, 12391233508580850, -136052492985945900, 674608025957515650, -1713147048499887000, 2313226290268018125, -1579311121869731250, 428670161650355625], ...
where e.g.f. A(x,k) = Sum_{n>=1, r=1..n} T(n,r) * x^(2*n-1) * k^(2*r-1) / (2*n-1)!.
E.g.f.: A(x,k) = k*x + (k^3 - k)*x^3/3! + (9*k^5 - 10*k^3 + k)*x^5/5! + (225*k^7 - 315*k^5 + 91*k^3 - k)*x^7/7! + (11025*k^9 - 18900*k^7 + 8694*k^5 - 820*k^3 + k)*x^9/9! + (893025*k^11 - 1819125*k^9 + 1143450*k^7 - 224730*k^5 + 7381*k^3 - k)*x^11/11! + (108056025*k^13 - 255405150*k^11 + 203378175*k^9 - 61647300*k^7 + 5684679*k^5 - 66430*k^3 + k)*x^13/13! + (18261468225*k^15 - 49165491375*k^13 + 47377655325*k^11 - 19494349875*k^9 + 3162834675*k^7 - 142714845*k^5 + 597871*k^3 - k)*x^15/15! + (4108830350625*k^17 - 12417798393000*k^15 + 14041664336700*k^13 - 7311738634200*k^11 + 1734021238950*k^9 - 158546770200*k^7 + 3573251964*k^5 - 5380840*k^3 + k)*x^17/17! + (1187451971330625*k^19 - 3981456609755625*k^17 + 5167045911327300*k^15 - 3257761647640500*k^13 + 1025176095093150*k^11 - 148224512094750*k^9 + 7858123038900*k^7 - 89379726660*k^5 + 48427561*k^3 - k)*x^19/19! +...
such that sin(A(x,k)) = k * sin(x).
-
T[n_, k_] := If[ n < 1, 0, (2 n - 1)! Coefficient[ SeriesCoefficient[ ArcSin[y Sin[x]], {x, 0, 2 n - 1}], y, 2 k - 1]]; (* Michael Somos, Jul 03 2018 *)
T[n_, k_] := ((-1)^n/((2*k - 1)^2*4^(2*k - 1)))*((2*k)!/k!)^2 * Sum[((-1)^i*(2*i - 1)^(2*n - 1))/((k - i)!*(k + i - 1)!), {i, 1, n}]; (* Vjekoslav-Leonard Prcic, Oct 10 2018 *)
-
{T(n, r) = (2*n-1)! * polcoeff( polcoeff( asin( k*sin(x + O(x^(2*n)))), 2*n-1,x), 2*r-1, k)}
for(n=1, 10, for(r=1, n, print1(T(n, r), ", ")); print(""))
A218725
a(n) = (22^n - 1)/21.
Original entry on oeis.org
0, 1, 23, 507, 11155, 245411, 5399043, 118778947, 2613136835, 57489010371, 1264758228163, 27824681019587, 612142982430915, 13467145613480131, 296277203496562883, 6518098476924383427, 143398166492336435395, 3154759662831401578691, 69404712582290834731203
Offset: 0
Cf. similar sequences of the form (k^n-1)/(k-1):
A000225,
A003462,
A002450,
A003463,
A003464,
A023000,
A023001,
A002452,
A002275,
A016123,
A016125,
A091030,
A135519,
A135518,
A131865,
A091045,
A218721,
A218722,
A064108,
A218724-
A218734,
A132469,
A218736-
A218753,
A133853,
A094028,
A218723.
-
[n le 2 select n-1 else 23*Self(n-1) - 22*Self(n-2): n in [1..20]]; // Vincenzo Librandi, Nov 07 2012
-
LinearRecurrence[{23, -22}, {0, 1}, 30] (* Vincenzo Librandi, Nov 07 2012 *)
-
A218725(n):=(22^n-1)/21$ makelist(A218725(n),n,0,30); /* Martin Ettl, Nov 06 2012 */
-
A218725(n)=22^n\21
A218737
a(n) = (34^n - 1)/33.
Original entry on oeis.org
0, 1, 35, 1191, 40495, 1376831, 46812255, 1591616671, 54114966815, 1839908871711, 62556901638175, 2126934655697951, 72315778293730335, 2458736461986831391, 83597039707552267295, 2842299350056777088031, 96638177901930420993055, 3285698048665634313763871
Offset: 0
Cf. similar sequences of the form (k^n-1)/(k-1):
A000225,
A003462,
A002450,
A003463,
A003464,
A023000,
A023001,
A002452,
A002275,
A016123,
A016125,
A091030,
A135519,
A135518,
A131865,
A091045,
A218721,
A218722,
A064108,
A218724-
A218734,
A132469,
A218736-
A218753,
A133853,
A094028,
A218723.
-
[n le 2 select n-1 else 35*Self(n-1)-34*Self(n-2): n in [1..20]]; // Vincenzo Librandi, Nov 07 2012
-
LinearRecurrence[{35, -34}, {0, 1}, 30] (* Vincenzo Librandi, Nov 07 2012 *)
-
A218737(n):=(34^n-1)/33$
makelist(A218737(n),n,0,30); /* Martin Ettl, Nov 07 2012 */
-
A218737(n)=34^n\33
A218738
a(n) = (35^n - 1)/34.
Original entry on oeis.org
0, 1, 36, 1261, 44136, 1544761, 54066636, 1892332261, 66231629136, 2318107019761, 81133745691636, 2839681099207261, 99388838472254136, 3478609346528894761, 121751327128511316636, 4261296449497896082261, 149145375732426362879136, 5220088150634922700769761
Offset: 0
Cf. similar sequences of the form (k^n-1)/(k-1):
A000225,
A003462,
A002450,
A003463,
A003464,
A023000,
A023001,
A002452,
A002275,
A016123,
A016125,
A091030,
A135519,
A135518,
A131865,
A091045,
A218721,
A218722,
A064108,
A218724-
A218734,
A132469,
A218736-
A218753,
A133853,
A094028,
A218723.
-
[n le 2 select n-1 else 36*Self(n-1)-35*Self(n-2): n in [1..20]]; // Vincenzo Librandi, Nov 07 2012
-
LinearRecurrence[{36, -35}, {0, 1}, 30] (* Vincenzo Librandi, Nov 07 2012 *)
-
A218738(n):=(35^n-1)/34$
makelist(A218738(n),n,0,30); /* Martin Ettl, Nov 07 2012 */
-
A218738(n)=35^n\34
Comments