A131082 -id:A131082 - cp's OEIS frontend

A131074 Triangular array T read by rows: T(j,1) = 1 for ((j-1) mod 8) < 4, else 0; T(j,k) = T(j-1,k-1) + T(j,k-1) for 2 <= k <= j.

1, 1, 2, 1, 2, 4, 1, 2, 4, 8, 0, 1, 3, 7, 15, 0, 0, 1, 4, 11, 26, 0, 0, 0, 1, 5, 16, 42, 0, 0, 0, 0, 1, 6, 22, 64, 1, 1, 1, 1, 1, 2, 8, 30, 94, 1, 2, 3, 4, 5, 6, 8, 16, 46, 140, 1, 2, 4, 7, 11, 16, 22, 30, 46, 92, 232, 1, 2, 4, 8, 15, 26, 42, 64, 94, 140, 232, 464, 0, 1, 3, 7, 15, 30, 56, 98

Offset: 1

Klaus Brockhaus, following a suggestion of Paul Curtz, Jun 14 2007

All columns are periodic with period length 8. The (4+8*i)-th row equals the first (4+8*i) terms of the main diagonal (i >= 0). Main diagonal and eighth subdiagonal agree; generally j-th subdiagonal equals (j+8)-th subdiagonal.

			First seven rows of T are
[ 1 ]
[ 1, 2 ]
[ 1, 2, 4 ]
[ 1, 2, 4, 8 ]
[ 0, 1, 3, 7, 15 ]
[ 0, 0, 1, 4, 11, 26 ]
[ 0, 0, 0, 1, 5, 16, 42 ].

Cf. A131022, A129961 (main diagonal of T), A131075 (first subdiagonal of T), A131076 (row sums of T), A131077 (antidiagonal sums of T). First through sixth column of T are in A131078, A131079, A131080, A131081, A131082, A131083 resp.

m:=13; M:=ZeroMatrix(IntegerRing(), m, m); for j:=1 to m do if (j-1) mod 8 lt 4 then M[j, 1]:=1; end if; end for; for k:=2 to m do for j:=k to m do M[j, k]:=M[j-1, k-1]+M[j, k-1]; end for; end for; &cat[ [ M[j, k]: k in [1..j] ]: j in [1..m] ];

T[j_, 1] := If[Mod[j-1, 8]<4, 1, 0]; T[j_, k_] := T[j, k] = T[j-1, k-1]+T[j, k-1]; Table[T[j, k], {j, 1, 13}, {k, 1, j}] // Flatten (* Jean-François Alcover, Mar 06 2014 *)

{m=13; M=matrix(m, m); for(j=1, m, M[j, 1]=if((j-1)%8<4, 1, 0)); for(k=2, m, for(j=k, m, M[j, k]=M[j-1, k-1]+M[j, k-1])); for(j=1, m, for(k=1, j, print1(M[j, k], ",")))}

A129961 Main diagonal of triangular array T: T(j,1) = 1 for ((j-1) mod 8) < 4, else 0; T(j,k) = T(j-1,k-1)+T(j,k-1) for 2 <= k <= j.

Original entry on oeis.org

1, 2, 4, 8, 15, 26, 42, 64, 94, 140, 232, 464, 1092, 2744, 6840, 16384, 37384, 81296, 169120, 338240, 654192, 1232288, 2280864, 4194304, 7761376, 14635712, 28384384, 56768768, 116566080, 243472256, 511907712, 1073741824, 2232713344

Offset: 1

Paul Curtz, Jun 10 2007

nonn

First column is periodically 1 1 1 1 0 0 0 0 (see A131078).
First subdiagonal is 1, 2, 4, 7, 11, 16, 22, ... (see A131075); next subdiagonals are 1, 2, 3, 4, 5, 6, 8, 16, 46, 140, ..., 1, 1, 1, 1, 1, 2, 8, 30, 94, 256, ..., 0, 0, 0, 0, 1, 6, 22, 64, 162, 372, ..., 0, 0, 0, 1, 5, 16, 42, 98, 210, 420, ...., 0, 0, 1, 4, 11, 26, 56, 112, 210, 372, ..., 0, 1, 3, 7, 15, 30, 56, 98, 162, 256, ...,1, 2, 4, 8, 15, 26, 42, 64, 94, 140, ... . Main diagonal and eighth subdiagonal agree; generally j-th subdiagonal equals (j+8)-th subdiagonal.
Antidiagonal sums are 1, 1, 3, 3, 6, 5, 11, ... (see A131077).

			First seven rows of T are
[ 1 ]
[ 1, 2 ]
[ 1, 2, 4 ]
[ 1, 2, 4, 8 ]
[ 0, 1, 3, 7, 15 ]
[ 0, 0, 1, 4, 11, 26 ]
[ 0, 0, 0, 1, 5, 16, 42 ].

Cf. A129339, A131074 (T read by rows), A131075 (first subdiagonal of T), A131076 (row sums of T), A131077 (antidiagonal sums of T). First through sixth column of T are in A131078, A131079, A131080, A131081, A131082, A131083 resp.

m:=33; M:=ZeroMatrix(IntegerRing(), m, m); for j:=1 to m do if (j-1) mod 8 lt 4 then M[j, 1]:=1; end if; end for; for k:=2 to m do for j:=k to m do M[j, k]:=M[j-1, k-1]+M[j, k-1]; end for; end for; [ M[n, n]: n in [1..m] ]; // Klaus Brockhaus, Jun 14 2007

m:=33; S:=[ [1, 1, 1, 1, 0, 0, 0, 0][(n-1) mod 8 + 1]: n in [1..m] ]; [ &+[ Binomial(i-1, k-1)*S[k]: k in [1..i] ]: i in [1..m] ]; // Klaus Brockhaus, Jun 17 2007

{m=33; v=concat([1, 2, 4, 8, 15], vector(m-5)); for(n=6, m, v[n]=6*v[n-1]-14*v[n-2]+16*v[n-3]-10*v[n-4]+4*v[n-5]); v} \\ Klaus Brockhaus, Jun 14 2007

G.f.: x*(1-x)^4/((1-2*x)*(1-4*x+6*x^2-4*x^3+2*x^4)).
a(1) = 1, a(2) = 2, a(3) = 4, a(4) = 8, a(5) = 15; for n > 5, a(n) = 6*a(n-1)-14*a(n-2)+16*a(n-3)-10*a(n-4)+4*a(n-5).
Binomial transform of A131078. - Klaus Brockhaus, Jun 17 2007

Edited and extended by Klaus Brockhaus, Jun 14 2007

G.f. corrected by Klaus Brockhaus, Oct 15 2009

A131075 First subdiagonal of triangular array T: T(j,1) = 1 for ((j-1) mod 8) < 4, else 0; T(j,k) = T(j-1,k-1) + T(j,k-1) for 2 <= k <= j.

Original entry on oeis.org

1, 2, 4, 7, 11, 16, 22, 30, 46, 92, 232, 628, 1652, 4096, 9544, 21000, 43912, 87824, 169120, 315952, 578096, 1048576, 1913440, 3567072, 6874336, 13748672, 28384384, 59797312, 126906176, 268435456, 561834112, 1158971520, 2353246336, 4706492672, 9292452352

Offset: 1

Klaus Brockhaus, following a suggestion of Paul Curtz, Jun 14 2007

Also first differences of main diagonal A129961.

			For first seven rows of T see A131074 or A129961.

Index entries for linear recurrences with constant coefficients, signature (6,-14,16,-10,4).

Cf. A131074 (T read by rows), A129961 (main diagonal of T), A131076 (row sums of T), A131077 (antidiagonal sums of T). First through sixth column of T are in A131078, A131079, A131080, A131081, A131082, A131083 resp.

m:=34; M:=ZeroMatrix(IntegerRing(), m, m); for j:=1 to m do if (j-1) mod 8 lt 4 then M[j, 1]:=1; end if; end for; for k:=2 to m do for j:=k to m do M[j, k]:=M[j-1, k-1]+M[j, k-1]; end for; end for; [ M[n+1, n]: n in [1..m-1] ];

lista(m) = my(v=concat([1, 2, 4, 7, 11], vector(m-5))); for(n=6, m, v[n]=6*v[n-1]-14*v[n-2]+16*v[n-3]-10*v[n-4]+4*v[n-5]); v

a(1) = 1, a(2) = 2, a(3) = 4, a(4) = 7, a(5) = 11; for n > 5, a(n) = 6*a(n-1)-14*a(n-2)+16*a(n-3)-10*a(n-4)+4*a(n-5).

G.f.: x*(1-4*x+6*x^2-5*x^3+3*x^4)/((1-2*x)*(1-4*x+6*x^2-4*x^3+2*x^4)).

A131076 Row sums of triangular array T: T(j,1) = 1 for ((j-1) mod 8) < 4, else 0; T(j,k) = T(j-1,k-1) + T(j,k-1) for 2 <= k <= j.

Original entry on oeis.org

1, 3, 7, 15, 26, 42, 64, 93, 139, 231, 463, 1092, 2744, 6840, 16384, 37383, 81295, 169119, 338239, 654192, 1232288, 2280864, 4194304, 7761375, 14635711, 28384383, 56768767, 116566080, 243472256, 511907712, 1073741824, 2232713343, 4585959679, 9292452351

Offset: 1

Klaus Brockhaus, following a suggestion of Paul Curtz, Jun 14 2007

Sum of n-th row equals (n+1)-th term of main diagonal minus (n+1)-th term of first column: a(n) = A129961(n+1) - A131078(n+1).

			For first seven rows of T see A131074 or A129961.

Index entries for linear recurrences with constant coefficients, signature (7,-20,30,-27,21,-24,30,-26,14,-4).

Cf. A131074 (T read by rows), A129961 (main diagonal of T), A131075 (first subdiagonal of T), A131077 (antidiagonal sums of T). First through sixth column of T are in A131078, A131079, A131080, A131081, A131082, A131083 resp.

m:=32; M:=ZeroMatrix(IntegerRing(), m, m); for j:=1 to m do if (j-1) mod 8 lt 4 then M[j, 1]:=1; end if; end for; for k:=2 to m do for j:=k to m do M[j, k]:=M[j-1, k-1]+M[j, k-1]; end for; end for; [ &+[ M[j, k]: k in [1..j] ]: j in [1..m] ];

LinearRecurrence[{7,-20,30,-27,21,-24,30,-26,14,-4},{1,3,7,15,26,42,64,93,139,231},40] (* Harvey P. Dale, Jun 23 2025 *)

lista(m) = my(M=matrix(m, m)); for(j=1, m, M[j, 1]=if((j-1)%8<4, 1, 0)); for(k=2, m, for(j=k, m, M[j, k]=M[j-1, k-1]+M[j, k-1])); for(j=1, m, print1(sum(k=1, j, M[j, k]), ", "))

G.f.: x*(1-4*x+6*x^2-4*x^3-2*x^4+10*x^5-10*x^6+5*x^7-x^8)/((1-x)*(1-2*x)*(1+x^4)*(1-4*x+6*x^2-4*x^3+2*x^4)).

A131077 Antidiagonal sums of triangular array T: T(j,1) = 1 for ((j-1) mod 8) < 4, else 0; T(j,k) = T(j-1,k-1) + T(j,k-1) for 2 <= k <= j.

Original entry on oeis.org

1, 1, 3, 3, 6, 5, 11, 8, 20, 14, 35, 24, 59, 41, 100, 77, 178, 162, 341, 364, 705, 837, 1542, 1915, 3458, 4282, 7741, 9280, 17021, 19461, 36482, 39559, 76042, 78218, 154261, 151184, 305445, 287509, 592954, 542223, 1135178, 1023210, 2158389, 1949312, 4107701

Offset: 1

Klaus Brockhaus, following a suggestion of Paul Curtz, Jun 14 2007

			For first seven rows of T see A131074 or A129961.

Index entries for linear recurrences with constant coefficients, signature (1,6,-6,-15,15,22,-22,-24,24,20,-20,-10,10,4,-4).

Cf. A131074 (T read by rows), A129961 (main diagonal of T), A131075 (first subdiagonal of T), A131076 (row sums of T). First through sixth column of T are in A131078, A131079, A131080, A131081, A131082, A131083 resp.

m:=44; M:=ZeroMatrix(IntegerRing(), m, m); for j:=1 to m do if (j-1) mod 8 lt 4 then M[j, 1]:=1; end if; end for; for k:=2 to m do for j:=k to m do M[j, k]:=M[j-1, k-1]+M[j, k-1]; end for; end for; [ &+[ M[j-k+1, k]: k in [1..(j+1) div 2] ]: j in [1..m] ];

lista(m) = my(M=matrix(m, m)); for(j=1, m, M[j, 1]=if((j-1)%8<4, 1, 0)); for(k=2, m, for(j=k, m, M[j, k]=M[j-1, k-1]+M[j, k-1])); for(j=1, m, print1(sum(k=1, (j+1)\2, M[j-k+1, k]), ", "))

G.f.: x*(1-4*x^2+6*x^4-x^5-4*x^6+3*x^7+x^8-3*x^9+x^10+2*x^11-x^12) / ((1-x)*(1-2*x^2)*(1+x^4)*(1-4*x^2+6*x^4-4*x^6+2*x^8)).

A137002 Numbers k such that k and k^2 use only the digits 1, 2 and 5.

Original entry on oeis.org

1, 5, 11, 15

Offset: 1

Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008

Sequence terminates.
Generated with DrScheme.
Numbers appearing in A131082; subsequence of A031153, A137003. - M. F. Hasler, Jan 24 2008

			15^2 = 225.

Jonathan Wellons, Tables of Shared Digits [archived]

Cf. A031153, A131082, A136986, A137003.

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A131074 Triangular array T read by rows: T(j,1) = 1 for ((j-1) mod 8) < 4, else 0; T(j,k) = T(j-1,k-1) + T(j,k-1) for 2 <= k <= j.

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A129961 Main diagonal of triangular array T: T(j,1) = 1 for ((j-1) mod 8) < 4, else 0; T(j,k) = T(j-1,k-1)+T(j,k-1) for 2 <= k <= j.

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A131075 First subdiagonal of triangular array T: T(j,1) = 1 for ((j-1) mod 8) < 4, else 0; T(j,k) = T(j-1,k-1) + T(j,k-1) for 2 <= k <= j.

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A131076 Row sums of triangular array T: T(j,1) = 1 for ((j-1) mod 8) < 4, else 0; T(j,k) = T(j-1,k-1) + T(j,k-1) for 2 <= k <= j.

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A131077 Antidiagonal sums of triangular array T: T(j,1) = 1 for ((j-1) mod 8) < 4, else 0; T(j,k) = T(j-1,k-1) + T(j,k-1) for 2 <= k <= j.

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A137002 Numbers k such that k and k^2 use only the digits 1, 2 and 5.

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