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.

Showing 1-4 of 4 results.

A096884 a(n) = 101^n.

Original entry on oeis.org

1, 101, 10201, 1030301, 104060401, 10510100501, 1061520150601, 107213535210701, 10828567056280801, 1093685272684360901, 110462212541120451001, 11156683466653165551101, 1126825030131969720661201, 113809328043328941786781301, 11494742132376223120464911401, 1160968955369998535166956051501
Offset: 0

Views

Author

Paul Barry, Jul 14 2004

Keywords

Comments

A185817(n) = smallest m such that in decimal representation n is a prefix of a(m).
a(n) gives the n-th row of Pascals' triangle (A007318) as long as all the binomial coefficients have at most two digits, otherwise the binomial coefficients with more than two digits overlap. - Daniel Forgues, Aug 12 2012
From Peter M. Chema, Apr 10 2016: (Start)
One percent growth applied n times increases a value by factor of a(n)/10^(2n), since 1% increases using "1.01". Therefore (a(n)/10^(2n) - 1)*100 = the percentage increase of one percent growth applied n times.
For instance, 432 increasing by 1% three times gives 445.090032 (i.e., 432*1.01^3), which is 1.030301 (a(3)/10^(2*3)) times 432 or a 3.0301% increase from the original 432 ((a(3)/10^(2*3)-1)*100 = 3.0301). (End)

Crossrefs

Programs

Formula

a(n) = Sum_{k=0..n} binomial(n, k)*10^(n-k).
a(n) = A096883(2n).
a(n) = 101^n. a(n) = Sum_{k=0..n,} binomial(n, k)*100^k. - Paul Barry, Aug 24 2004
G.f.: 1/(1-101*x). - Philippe Deléham, Nov 25 2008
E.g.f.: exp(101*x). - Ilya Gutkovskiy, Apr 10 2016

A133342 Concatenation of binary expansion of n-th row of Pascal's triangle.

Original entry on oeis.org

1, 11, 1101, 111111, 11001101001, 1101101010101011, 111011111010011111101, 111110101100011100011101011111, 110001110011100010001101110001110010001, 11001100100101010011111101111110101010010010010011
Offset: 0

Views

Author

Jonathan Vos Post, Oct 20 2007

Keywords

Comments

Binary analog of A003590. More generally, this sequence is the 2nd row of the matrix whose k-th row is the concatenation of the base-k expression of n-th row of Pascal's triangle. The 10th row of that array is A003590.
a(n) is a repunit for n = 0, 1, 3, but otherwise not since C(n,1) = n has a 0-bit apart from at n=2^k-1 and there C(n,2) = n*(n-1)/2 == 1 (mod 4) has a 0-bit. - Kevin Ryde and Bernard Schott, Nov 11 2021

Examples

			a(0) = 1 because the 0th row of Pascal's triangle is 1.
a(1) = 11 because the 1st row of Pascal's triangle is 1,1 which concatenates to 11.
a(2) = 1101 because the 2nd row of Pascal's triangle is 1,2,1 which in binary is 1,10,1 which concatenates to 1101.
a(3) = 111111 because the 3rd row of Pascal's triangle is 1,3,3,1 which in binary is 1,11,11,1 which concatenates to 111111.
a(4) = 110010101001 because the 4th row of Pascal's triangle is 1,4,6,4,1 which in binary is 1,100,110,100,1 which concatenates to 11001101001.
a(5) = 1101101010101011 because the 5th row of Pascal's triangle is 1,5,10,10,5,1 which in binary is 1,101,1010,1010,101,1 which concatenates to 1101101010101011.
a(6) = 111011111010011111101 because the 6th row of Pascal's triangle is 1,6,15,20,15,6,1 which in binary is 1,110,1111,10100,1111,110,1 which concatenates to 111011111010011111101.
The array of base k concatenations begins:
  k/n  0  1   2    3        4
  1.|  1  11  1111 11111111 1111111111111111  2^(n-1) repetitions of 1
  2.|  1  11  1101 111111   11001101001
  3.|  1  11  121  110101   11120111
  4.|  1  11  121  1331     11012101
  5.|  1  11  121  1331     141141
  6.|  1  11  121  1331     141041
		

Crossrefs

Programs

  • Maple
    catL := proc(L) local resul,a ; resul:=0 ; for a in L do resul := resul*10^(max(ilog10(a)+1,1))+a ; od: RETURN(resul) ; end: A133342 := proc(n) local prow,k ; prow := [1] ; for k from 1 to n do prow := [op(prow), convert(binomial(n,k),binary) ] ; od: catL(prow) ; end: seq(A133342(n),n=0..11) ; # R. J. Mathar, Jan 08 2008
  • Mathematica
    FromDigits[Flatten[IntegerDigits[#,2]]]&/@Table[Binomial[n,k],{n,0,10},{k,0,n}] (* Harvey P. Dale, Apr 12 2020 *)

Formula

a(n) = Concatenate[k=1..n] binomial(n, k) (base 2).
a(n) = Concatenate[i=A000217(n)..A000217(n+1)] A007088(A007318(i)).

Extensions

Corrected and extended by R. J. Mathar, Jan 08 2008

A349304 Terms of sequence A133342 interpreted as numbers written in base 2 and converted here to base 10.

Original entry on oeis.org

1, 3, 13, 63, 1641, 55979, 1963261, 1051838303, 427823653777, 899765549835411, 962612860717614517, 16451240378526759988983, 275851420933163891499583577, 75079775107059278497058879826395, 1275913767034795679914048924532788093, 1386272923043819758818080175342943182028095
Offset: 0

Views

Author

Bernard Schott, Nov 14 2021

Keywords

Comments

a(n) is a Mersenne number (A000225) iff n = 0, 1, 3 (see proof in A133342).

Crossrefs

Programs

  • Mathematica
    a[n_] := FromDigits[Join @@ Table[IntegerDigits[Binomial[n, k], 2], {k, 0, n}], 2]; Array[a, 15, 0] (* Amiram Eldar, Nov 14 2021 *)
  • PARI
    a(n) = fromdigits(concat(vector(n+1, k, binary(binomial(n, k-1)))), 2); \\ Michel Marcus, Nov 14 2021

A369152 Total number of digits in row n of Pascal's triangle.

Original entry on oeis.org

1, 2, 3, 4, 5, 8, 10, 12, 14, 18, 25, 28, 31, 38, 44, 50, 57, 64, 69, 76, 88, 96, 102, 114, 125, 134, 142, 154, 166, 178, 191, 202, 215, 230, 244, 256, 268, 288, 303, 316, 334, 356, 372, 388, 411, 428, 447, 470, 490, 506, 529, 554, 573, 590, 618, 642, 660, 686
Offset: 0

Views

Author

Bartlomiej Pawlik, Jan 14 2024

Keywords

Crossrefs

Programs

  • Maple
    a:= n-> length(cat(seq(binomial(n,k), k=0..n))):
    seq(a(n), n=0..57);  # Alois P. Heinz, Jan 15 2024
  • Mathematica
    A369152[n_Integer] := Total[IntegerLength[Binomial[n, #]] & /@ Range[0, n]]
    First50Terms = Table[A369152[n], {n, 0, 49}]
  • PARI
    a(n) = #concat(vector(n+1, k, Str(binomial(n,k-1)))); \\ Michel Marcus, Jan 18 2024
    
  • Python
    from math import comb
    def A369152(n): return sum(len(str(comb(n,k))) for k in range(n+1)) # Chai Wah Wu, Feb 15 2024

Formula

a(n) = 1 + n + Sum_{k=0..n} floor(log_10(C(n,k))).
a(n) = A055642(A003590(n)). - Michel Marcus, Jan 15 2024
Showing 1-4 of 4 results.