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.

Previous Showing 11-16 of 16 results.

A095145 Triangle, read by rows, formed by reading Pascal's triangle (A007318) mod 12.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 6, 4, 1, 1, 5, 10, 10, 5, 1, 1, 6, 3, 8, 3, 6, 1, 1, 7, 9, 11, 11, 9, 7, 1, 1, 8, 4, 8, 10, 8, 4, 8, 1, 1, 9, 0, 0, 6, 6, 0, 0, 9, 1, 1, 10, 9, 0, 6, 0, 6, 0, 9, 10, 1, 1, 11, 7, 9, 6, 6, 6, 6, 9, 7, 11, 1, 1, 0, 6, 4, 3, 0, 0, 0, 3, 4, 6, 0, 1, 1, 1, 6, 10, 7, 3, 0, 0, 3, 7, 10, 6, 1, 1
Offset: 0

Views

Author

Robert G. Wilson v, May 29 2004

Keywords

Crossrefs

Sequences based on the triangles formed by reading Pascal's triangle mod m: A047999 (m = 2), A083093 (m = 3), A034931 (m = 4), A095140 (m = 5), A095141 (m = 6), A095142 (m = 7), A034930 (m = 8), A095143 (m = 9), A008975 (m = 10), A095144 (m = 11), (this sequence) (m = 12), A275198 (m = 14), A034932 (m = 16).

Programs

  • Mathematica
    Mod[ Flatten[ Table[ Binomial[n, k], {n, 0, 13}, {k, 0, n}]], 12]
  • Python
    # uses python code from A034931 and A083093
    from sympy.ntheory.modular import crt
    def A095145(n): return crt([4,3],[A034931(n),A083093(n)])[0] # Chai Wah Wu, Jul 19 2025

Formula

T(i, j) = binomial(i, j) mod 12.

A275198 Triangle, read by rows, formed by reading Pascal's triangle (A007318) mod 14.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 6, 4, 1, 1, 5, 10, 10, 5, 1, 1, 6, 1, 6, 1, 6, 1, 1, 7, 7, 7, 7, 7, 7, 1, 1, 8, 0, 0, 0, 0, 0, 8, 1, 1, 9, 8, 0, 0, 0, 0, 8, 9, 1, 1, 10, 3, 8, 0, 0, 0, 8, 3, 10, 1, 1, 11, 13, 11, 8, 0, 0, 8, 11, 13, 11, 1, 1, 12, 10, 10, 5, 8, 0, 8, 5, 10, 10, 12, 1, 1, 13, 8, 6, 1, 13, 8, 8, 13, 1, 6, 8, 13, 1, 1, 0, 7, 0, 7, 0, 7, 2, 7, 0, 7, 0, 7, 0, 1
Offset: 0

Views

Author

Ilya Gutkovskiy, Aug 11 2016

Keywords

Examples

			Triangle begins:
                      1,
                    1,  1,
                  1,  2,  1,
                1,  3,  3,  1,
              1,  4,  6,  4,  1,
            1,  5, 10, 10,  5,  1,
          1,  6,  1,  6,  1,  6,  1,
        1,  7,  7,  7,  7,  7,  7,  1,
      1,  8,  0,  0,  0,  0,  0,  8,  1,
    1,  9,  8,  0,  0,  0,  0,  8,  9,  1,
  1, 10,  3,  8,  0,  0,  0,  8,  3, 10,  1,
  ...
		

Crossrefs

Sequences based on the triangles formed by reading Pascal's triangle mod m: A047999 (m = 2), A083093 (m = 3), A034931 (m = 4), A095140 (m = 5), A095141 (m = 6), A095142 (m = 7), A034930 (m = 8), A095143 (m = 9), A008975 (m = 10), A095144 (m = 11), A095145 (m = 12), (this sequence) (m = 14), A034932 (m = 16).

Programs

  • Mathematica
    Mod[Flatten[Table[Binomial[n, k], {n, 0, 14}, {k, 0, n}]], 14]
  • Python
    from math import comb, isqrt
    from sympy.ntheory.modular import crt
    def A275198(n):
        w, c = n-((r:=(m:=isqrt(k:=n+1<<1))-(k<=m*(m+1)))*(r+1)>>1), 1
        d = int(not ~r & w)
        while True:
            r, a = divmod(r,7)
            w, b = divmod(w,7)
            c = c*comb(a,b)%7
            if r<7 and w<7:
                c = c*comb(r,w)%7
                break
        return crt([7,2],[c,d])[0] # Chai Wah Wu, May 01 2025

Formula

T(n, k) = binomial(n, k) mod 14.
a(n) = A070696(A007318(n)).

A385285 a(n) = Sum_{k=0..n} (binomial(n, k) mod 8).

Original entry on oeis.org

1, 2, 4, 8, 16, 16, 32, 32, 16, 32, 24, 48, 40, 64, 40, 64, 16, 32, 40, 64, 48, 48, 88, 96, 40, 80, 88, 112, 72, 112, 112, 128, 16, 32, 40, 64, 64, 96, 120, 160, 48, 96, 72, 144, 104, 176, 160, 192, 40, 80, 104, 176, 120, 176, 176, 224, 72, 144, 160, 224, 176
Offset: 0

Views

Author

Peter Luschny, Jun 26 2025

Keywords

Comments

a(n) is a multiple of A001316(n). - Chai Wah Wu, Jun 26 2025

Crossrefs

Cf. A034930 (row sums of), A001316 (mod 2), A384715 (mod 4).

Programs

  • Maple
    A385285 := n -> local k; add(modp(binomial(n, k), 8), k = 0..n): seq(A385285(n), n = 0..60);
  • Mathematica
    A385285[n_] := Sum[Mod[Binomial[n, k], 8], {k, 0, n}];
    Array[A385285, 100, 0] (* Paolo Xausa, Jun 26 2025 *)
  • PARI
    a(n) = sum(k=0, n, binomial(n, k) % 8); \\ Michel Marcus, Jun 26 2025
    
  • Python
    def A385285(n):
        if n==0: return 1
        s = '0'+bin(n)[2:]
        n1 = n>>1
        n2 = n1>>1
        n3 = n2>>1
        np = ~n
        n1111 = (n3&n2&n1&n).bit_count()
        n11 = (n1&n).bit_count()
        n101 = (n2&(~n1)&n).bit_count()
        n100 = (n2&(~n1)&np).bit_count()
        n110 = (n2&n1&np).bit_count()
        n10 = (n1&np).bit_count()
        n1100 = (n3&n2&(~n1)&np).bit_count()
        m11 = s.count('0110')
        m111 = s.endswith('0111')
        c = (n100<<2)+n110+(n10*(n10-1)>>1)
        if n11==0:
            c += n10+(n100<<1)
        elif n11==1:
            c += (n10-n1100<<1)+n110
        else:
            c += n10<<1
        if not (n1111 or n11 or n101):
            c += 1
        elif not (n1111 or n11) and n101:
            c += 3
        elif m111:
            c += 4
        elif not (n1111 or n101 or m11) and n11:
            c += 2
        else:
            c += 4
        return c<Chai Wah Wu, Jun 26 2025

A213126 Rows of triangle formed using Pascal's rule, except sums in the n-th row are modulo n: T(n,0) = T(n,n) = 1 and T(n,k) = (T(n-1,k-1) + T(n-1,k)) mod n.

Original entry on oeis.org

1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 1, 3, 4, 4, 3, 1, 1, 4, 1, 2, 1, 4, 1, 1, 5, 5, 3, 3, 5, 5, 1, 1, 6, 2, 0, 6, 0, 2, 6, 1, 1, 7, 8, 2, 6, 6, 2, 8, 7, 1, 1, 8, 5, 0, 8, 2, 8, 0, 5, 8, 1, 1, 9, 2, 5, 8, 10, 10, 8, 5, 2, 9, 1, 1, 10, 11, 7, 1, 6, 8, 6
Offset: 0

Views

Author

Alex Ratushnyak, Jun 06 2012

Keywords

Examples

			Triangle begins:
  1;
  1,  1;
  1,  0,  1;
  1,  1,  1,  1;
  1,  2,  2,  2,  1;
  1,  3,  4,  4,  3,  1;
  1,  4,  1,  2,  1,  4,  1;
  1,  5,  5,  3,  3,  5,  5,  1;
  1,  6,  2,  0,  6,  0,  2,  6,  1;
  1,  7,  8,  2,  6,  6,  2,  8,  7,  1;
  1,  8,  5,  0,  8,  2,  8,  0,  5,  8,  1;
  1,  9,  2,  5,  8, 10, 10,  8,  5,  2,  9,  1;
		

Crossrefs

Cf. A007318 - Pascal's triangle read by rows.

Programs

  • Mathematica
    T[n_,k_]:=If[k==0 || k==n, 1, Mod[T[n - 1, k - 1] + T[n- 1, k], n]]; Table[T[n, k], {n, 0, 15}, {k, 0, n}] // Flatten (* Indranil Ghosh, Apr 29 2017 *)
  • Python
    src = [0]*1024
    dst = [0]*1024
    for n in range(19):
        dst[0] = dst[n] = 1
        for k in range(1, n):
            dst[k] = (src[k-1]+src[k]) % n
        for k in range(n+1):
            src[k] = dst[k]
            print(dst[k], end=',')

Extensions

Offset corrected by Joerg Arndt, Dec 05 2016

A386441 Triangle, read by rows, formed by reading Pascal's triangle (A007318) mod 27.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 6, 4, 1, 1, 5, 10, 10, 5, 1, 1, 6, 15, 20, 15, 6, 1, 1, 7, 21, 8, 8, 21, 7, 1, 1, 8, 1, 2, 16, 2, 1, 8, 1, 1, 9, 9, 3, 18, 18, 3, 9, 9, 1, 1, 10, 18, 12, 21, 9, 21, 12, 18, 10, 1, 1, 11, 1, 3, 6, 3, 3, 6, 3, 1, 11, 1, 1, 12, 12, 4, 9, 9, 6, 9, 9, 4, 12, 12, 1, 1, 13, 24, 16, 13, 18, 15, 15, 18, 13, 16, 24, 13, 1
Offset: 0

Views

Author

Chai Wah Wu, Jul 21 2025

Keywords

Examples

			Triangle begins:
               1;
             1,  1;
           1,  2,  1;
         1,  3,  3,  1;
       1,  4,  6,  4,  1;
     1,  5,  10,  10,  5,  1;
   1,  6,  15,  20,  15,  6,  1;
 1,  7,  21,  8,   8,  21,  7,  1;
  ...
		

Crossrefs

Sequences based on the triangles formed by reading Pascal's triangle mod m: A047999 (m = 2), A083093 (m = 3), A034931 (m = 4), A095140 (m = 5), A095141 (m = 6), A095142 (m = 7), A034930 (m = 8), A095143 (m = 9), A008975 (m = 10), A095144 (m = 11), A095145 (m = 12), A275198 (m = 14), A034932 (m = 16).

Programs

  • Mathematica
    T[i_,j_]:=Mod[Binomial[i,j],27]; Table[T[n,k],{n,0,13},{k,0,n}]//Flatten (* Stefano Spezia, Jul 22 2025 *)
  • Python
    from math import isqrt, comb
    from sympy import multiplicity
    from gmpy2 import digits
    def A386441(n):
        def g1(s,w,e):
            c, d = 1, 0
            if len(s) == 0: return c, d
            a, b = int(s,3), int(w,3)
            if a>=b:
                k = comb(a,b)%27
                j = multiplicity(3,k)
                d += j*e
                k = k//3**j
                c = c*pow(k,e,27)%27
            else:
                if int(s[0:1],3)4: return 0
        s = s.zfill(3)
        w = w.zfill(l:=len(s))
        c, d = g1(s[:3],w[:3],1)
        for i in range(1,l-2):
            c0, d0 = g1(s[i:i+3],w[i:i+3],1)
            c1, d1 = g1(s[i:i+2],w[i:i+2],-1)
            c = c*c0*c1%27
            d += d0+d1
        return c*3**d%27

Formula

T(i, j) = binomial(i, j) mod 27.

A178206 Decimal representation of asymptotic growth constant for the number of acyclic orientations on the two-dimensional Sierpinski gasket SG2(n) in the large n limit.

Original entry on oeis.org

1, 1, 2, 7, 2, 9, 9, 0, 7, 0, 5, 3, 6, 6, 1, 6
Offset: 1

Views

Author

Jonathan Vos Post, May 22 2010

Keywords

Comments

Proposition III.1, p.10 of Chang. The paper also studies the number of acyclic orientations on the generalized two-dimensional Sierpinski gasket $SG_{2,b}(n)$ at stage $n$ with $b$ equal to two and three, and determines the asymptotic behaviors. It also derives upper bounds for the asymptotic growth constants for $SG_{2,b}$ and $d$-dimensional Sierpinski gasket $SG_d$.

Examples

			1.127299070536616....
		

Crossrefs

Previous Showing 11-16 of 16 results.