cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A085364 a(0)=1, for n>0: a(n) = 6*13^(n-1) - (1/2)*Sum_{i=1..n-1} a(i)*a(n-i).

Original entry on oeis.org

1, 6, 60, 654, 7458, 87378, 1042152, 12587730, 153479508, 1885010946, 23285957604, 289018502682, 3601315495050, 45023019250398, 564465885846216, 7094214579174558, 89351097367355826, 1127492973620753010
Offset: 0

Views

Author

Mario Catalani (mario.catalani(AT)unito.it), Jun 25 2003

Keywords

Comments

From G. C. Greubel, May 23 2020: (Start)
This sequence is part of a class of sequences, for m >= 0, with the properties:
a(n) = 2*m*(4*m+1)^(n-1) - (1/2)*Sum_{k=1..n-1} a(k)*a(n-k).
a(n) = Sum_{k=0..n} m^k * binomial(n-1, n-k) * binomial(2*k, k).
n*a(n) = 2*((2*m+1)*n - (m+1))*a(n-1) - (4*m+1)*(n-2)*a(n-2).
a(n) = (2*m) * Hypergeometric2F1(-n+1, 3/2; 2; -4*m), for n > 0.
(4*m + 1)^n = Sum_{k=0..n} Sum_{j=0..k} a(j)*a(k-j).
G.f.: sqrt( (1 - t)/(1 - (4*m+1)*t) ).
This sequence is the case of m=3. (End)

Crossrefs

Cf. A001022 (13^n), A085362, A085363.

Programs

  • Magma
    R:=PowerSeriesRing(Rationals(), 30); Coefficients(R!( Sqrt((1-x)/(1-13*x)) )); // G. C. Greubel, May 23 2020
    
  • Maple
    seq(coeff(series( sqrt((1-x)/(1-13*x)) , x, n+1), x, n), n = 0..30); # G. C. Greubel, May 23 2020
  • Mathematica
    CoefficientList[Series[Sqrt[(1-x)/(1-13x)], {x, 0, 25}], x]
  • PARI
    my(x='x+O('x^66)); Vec(sqrt((1-x)/(1-13*x))) \\ Joerg Arndt, May 10 2013
    
  • Sage
    def A085362_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( sqrt((1-x)/(1-13*x)) ).list()
    A085362_list(30) # G. C. Greubel, May 23 2020

Formula

G.f.: sqrt((1-x)/(1-13*x))
Sum_{i=0..n} Sum_{j=0..i} a(j)*a(i-j) = 13^n.
D-finite with recurrence: n*a(n) = 2*(7*n-4)*a(n-1) - 13*(n-2)*a(n-2). - Vaclav Kotesovec, Oct 14 2012
a(n) ~ 2*sqrt(3)*13^(n-1/2)/sqrt(Pi*n). - Vaclav Kotesovec, Oct 14 2012
a(0) = 1; a(n) = (6/n) * Sum_{k=0..n-1} (n+k) * a(k). - Seiichi Manyama, Mar 28 2023
From Seiichi Manyama, Aug 22 2025: (Start)
a(n) = (1/4)^n * Sum_{k=0..n} 13^k * binomial(2*k,k) * binomial(2*(n-k),n-k)/(1-2*(n-k)).
a(n) = Sum_{k=0..n} (-3)^k * 13^(n-k) * binomial(2*k,k)/(1-2*k) * binomial(n-1,n-k). (End)

A175434 (Digit sum of 2^n) mod n.

Original entry on oeis.org

0, 0, 2, 3, 0, 4, 4, 5, 8, 7, 3, 7, 7, 8, 11, 9, 14, 1, 10, 11, 5, 3, 18, 13, 4, 14, 8, 15, 12, 7, 16, 26, 29, 27, 24, 28, 19, 29, 32, 21, 9, 4, 13, 14, 17, 24, 21, 25, 16, 26, 29, 27, 24, 28, 37, 29, 23, 12, 18, 22, 13, 23, 26, 24, 21, 43, 43, 35, 20, 0, 15, 37, 37, 56, 50, 30, 27, 22, 31, 32, 26, 42, 39, 34, 43, 26, 20, 27, 24, 28, 55, 47, 32, 57, 45, 31, 40, 14, 8, 15
Offset: 1

Views

Author

N. J. A. Sloane, Dec 03 2010

Keywords

Examples

			For n = 1,2,3,4,5,6, the digit-sum of 2^n is 2,4,8,7,5,10, so
a(1) through a(6) are 0,0,2,3,0,4. - _N. J. A. Sloane_, Aug 12 2014
		

Crossrefs

Sum of digits of k^n mod n: (k=2) A000079, A001370, A175434, A175169; (k=3) A000244, A004166, A175435, A067862; (k=5) A000351, A066001, A175456; (k=6) A000400, A066002, A175457, A067864; (k=7) A000420, A066003, A175512, A067863; (k=8) A062933; (k=13) A001022, A175527, A175528, A175525; (k=21) A175589; (k=167) A175558, A175559, A175560, A175552.

Programs

  • Mathematica
    Table[Mod[Total[IntegerDigits[2^n]],n],{n,100}] (* Harvey P. Dale, Aug 12 2014 *)

Extensions

Offset changed to 1 at the suggestion of Harvey P. Dale, Aug 12 2014

A175528 (Digit sum of 13^n) mod n.

Original entry on oeis.org

0, 0, 1, 2, 0, 1, 5, 2, 1, 7, 8, 7, 6, 13, 13, 5, 3, 1, 9, 15, 7, 11, 14, 13, 21, 3, 10, 9, 17, 13, 29, 9, 16, 23, 29, 28, 27, 26, 4, 33, 9, 16, 23, 37, 10, 17, 6, 16, 2, 32, 49, 32, 29, 46, 17, 44, 43, 11, 50, 58, 32, 56, 10, 45, 33, 61, 60, 18, 67, 66, 47, 1, 17, 15, 22, 69, 18, 61, 5, 11, 73, 63, 42, 40, 29, 18, 7, 57, 12, 46, 53, 53, 49, 11, 18, 40, 84, 39, 37, 35
Offset: 1

Views

Author

N. J. A. Sloane, Dec 03 2010

Keywords

Crossrefs

Programs

  • Mathematica
    Array[Mod[Total[IntegerDigits[13^#]],#]&, 1000]

A038327 Triangle whose (i,j)-th entry is binomial(i,j)*12^(i-j)*1^j.

Original entry on oeis.org

1, 12, 1, 144, 24, 1, 1728, 432, 36, 1, 20736, 6912, 864, 48, 1, 248832, 103680, 17280, 1440, 60, 1, 2985984, 1492992, 311040, 34560, 2160, 72, 1, 35831808, 20901888, 5225472, 725760, 60480, 3024, 84, 1, 429981696, 286654464, 83607552
Offset: 0

Views

Author

Keywords

Comments

T(i,j) is the number of i-permutations of 13 objects a,b,c,d,e,f,g,h,i,j,k,l,m, with repetition allowed, containing j a's. - Zerinvary Lajos, Dec 21 2007
These are the rows of A013619 read right to left. Row sums are A001022(i). - R. J. Mathar, Mar 05 2008

Examples

			1
12, 1
144, 24, 1
1728, 432, 36, 1
20736, 6912, 864, 48, 1
248832, 103680, 17280, 1440, 60, 1
2985984, 1492992, 311040, 34560, 2160, 72, 1
35831808, 20901888, 5225472, 725760, 60480, 3024, 84, 1
		

References

  • B. N. Cyvin et al., Isomer enumeration of unbranched catacondensed polygonal systems with pentagons and heptagons, Match, No. 34 (Oct 1996), pp. 109-121.

Programs

  • Maple
    for i from 0 to 7 do seq(binomial(i, j)*12^(i-j), j = 0 .. i) od; # Zerinvary Lajos, Dec 21 2007

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

Views

Author

Keywords

Crossrefs

Bisection of A001022 (12^n).

Programs

Formula

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

A133371 Triangle read by rows: T(i,j) is the number of i-permutations of 14 objects a,b,c,d,e,f,g,h,i,j,k,l,m,n, with repetition allowed, containing j a's.

Original entry on oeis.org

1, 13, 1, 169, 26, 1, 2197, 507, 39, 1, 28561, 8788, 1014, 52, 1, 371293, 142805, 21970, 1690, 65, 1, 4826809, 2227758, 428415, 43940, 2535, 78, 1, 62748517, 33787663, 7797153, 999635, 76895, 3549, 91, 1
Offset: 0

Views

Author

Zerinvary Lajos, with help from Emeric Deutsch, Dec 21 2007

Keywords

Comments

Mirror image of A123187. - Philippe Deléham, Dec 27 2007

Examples

			1
13, 1
169, 26, 1
2197, 507, 39, 1
28561, 8788, 1014, 52, 1
371293, 142805, 21970, 1690, 65, 1
4826809, 2227758, 428415, 43940, 2535, 78, 1
62748517, 33787663, 7797153, 999635, 76895, 3549, 91, 1
		

Crossrefs

Programs

  • Maple
    for i from 0 to 7 do seq(binomial(i, j)*13^(i-j), j = 0 .. i) od;
  • Mathematica
    Flatten[Table[Binomial[i,j] 13^(i-j),{i,0,7},{j,0,i}]] (* Harvey P. Dale, Nov 01 2011 *)

A013752 a(n) = 13^(3*n + 1).

Original entry on oeis.org

13, 28561, 62748517, 137858491849, 302875106592253, 665416609183179841, 1461920290375446110677, 3211838877954855105157369, 7056410014866816666030739693, 15502932802662396215269535105521, 34059943367449284484947168626829637, 74829695578286078013428929473144712489
Offset: 0

Views

Author

Keywords

Crossrefs

Subsequence of A001022.
Cf. A013753.

Programs

Formula

From Philippe Deléham, Nov 30 2008: (Start)
a(n) = 2197*a(n-1); a(0)=13.
G.f.: 13/(1-2197*x).
a(n) = A013753(n)/13. (End)
E.g.f.: 13*exp(13^3*x). - Stefano Spezia, Aug 29 2024

A013753 a(n) = 13^(3*n + 2).

Original entry on oeis.org

169, 371293, 815730721, 1792160394037, 3937376385699289, 8650415919381337933, 19004963774880799438801, 41753905413413116367045797, 91733330193268616658399616009, 201538126434611150798503956371773, 442779263776840698304313192148785281, 972786042517719014174576083150881262357
Offset: 0

Views

Author

Keywords

Crossrefs

Subsequence of A001022.

Programs

Formula

From Philippe Deléham, Nov 30 2008: (Start)
a(n) = 2197*a(n-1); a(0)=169.
G.f.: 169/(1-2197*x).
a(n) = 13*A013752(n). (End)

A196792 a(n) = A047848(10, n).

Original entry on oeis.org

1, 2, 15, 184, 2381, 30942, 402235, 5229044, 67977561, 883708282, 11488207655, 149346699504, 1941507093541, 25239592216022, 328114698808275, 4265491084507564, 55451384098598321, 720867993281778162, 9371283912663116095, 121826690864620509224, 1583746981240066619901
Offset: 0

Views

Author

Vincenzo Librandi, Oct 11 2011

Keywords

Crossrefs

Cf. A001022 (first differences).

Programs

  • Magma
    [(13^n+11)/12: n in [0..20]];
    
  • Mathematica
    (13^Range[0,40] +11)/12 (* G. C. Greubel, Jan 17 2025 *)
  • Python
    def A196792(n): return (pow(13, n) + 11)//12
    print([A196792(n) for n in range(41)]) # G. C. Greubel, Jan 17 2025

Formula

a(n) = (13^n + 11)/12.
a(n) = 13*a(n-1) - 11, with a(0) = 1.
G.f.: (1-12*x)/((1-x)*(1-13*x)). - Bruno Berselli, Oct 11 2011
From Elmo R. Oliveira, Aug 30 2024: (Start)
E.g.f.: exp(x)*(exp(12*x) + 11)/12.
a(n) = 14*a(n-1) - 13*a(n-2) for n > 1. (End)

A319074 a(n) is the sum of the first n nonnegative powers of the n-th prime.

Original entry on oeis.org

1, 4, 31, 400, 16105, 402234, 25646167, 943531280, 81870575521, 15025258332150, 846949229880161, 182859777940000980, 23127577557875340733, 1759175174860440565844, 262246703278703657363377, 74543635579202247026882160, 21930887362370823132822661921, 2279217547342466764922495586798
Offset: 1

Views

Author

Omar E. Pol, Sep 11 2018

Keywords

Examples

			For n = 4 the 4th prime is 7 and the sum of the first four nonnegative powers of 7 is 7^0 + 7^1 + 7^2 + 7^3 = 1 + 7 + 49 + 343 = 400, so a(4) = 400.
		

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n-1, prime(n)^k); \\ Michel Marcus, Sep 13 2018

Formula

a(n) = Sum_{k=0..n-1} A000040(n)^k.
a(n) = Sum_{k=0..n-1} A319075(k,n).
a(n) = (A000040(n)^n - 1)/(A000040(n) - 1).
a(n) = (A062457(n) - 1)/A006093(n).
a(n) = A069459(n)/A006093(n).
a(n) = A000203(A000040(n)^(n-1)).
a(n) = A000203(A093360(n)).
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