A094760 Duplicate of A083956.
1, 33, 666, 11110, 166665, 2333331, 31111108, 399999996, 4999999995
Offset: 1
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.
a[0] = 1; a[n_] := a[n] = Block[{k = 1, s = Sum[a[i]*x^i, {i, 0, n-1}]}, While[ Union[ IntegerQ /@ CoefficientList[ Series[(s+k*x^n)^(1/8), {x, 0, n}], x]] != {True}, k++ ]; k]; Table[ a[n], {n, 0, 104}] (* Robert G. Wilson v *)
a[0] = 1; a[n_] := a[n] = Block[{k = 1, s = Sum[a[i]*x^i, {i, 0, n-1}]}, While[ Union[ IntegerQ /@ CoefficientList[ Series[(s+k*x^n)^(1/9), {x, 0, n}], x]] != {True}, k++ ]; k]; Table[ a[n], {n, 0, 104}] (* Robert G. Wilson v *)
a[0] = 1; a[n_] := a[n] = Block[{k = 1, s = Sum[a[i]*x^i, {i, 0, n-1}]}, While[ Union[ IntegerQ /@ CoefficientList[ Series[(s+k*x^n)^(1/10), {x, 0, n}], x]] != {True}, k++ ]; k]; Table[ a[n], {n, 0, 80}] (* Robert G. Wilson v *)
a[0] = 1; a[n_] := a[n] = Block[{k = 1, s = Sum[a[i]*x^i, {i, 0, n-1}]}, While[ Union[ IntegerQ /@ CoefficientList[ Series[(s+k*x^n)^(1/7), {x, 0, n}], x]] != {True}, k++ ]; k]; Table[ a[n], {n, 0, 104}] (* Robert G. Wilson v *)
a[0] = 1; a[n_] := a[n] = Block[{k = 1, s = Sum[a[i]*x^i, {i, 0, n-1}]}, While[ Union[ IntegerQ /@ CoefficientList[ Series[(s+k*x^n)^(1/12), {x, 0, n}], x]] != {True}, k++ ]; k]; Table[ a[n], {n, 0, 81}] (* Robert G. Wilson v *)
a[0] = 1; a[n_] := a[n] = Block[{k = 1, s = Sum[a[i]*x^i, {i, 0, n-1}]}, While[ Union[ IntegerQ /@ CoefficientList[ Series[(s+k*x^n)^(1/11), {x, 0, n}], x]] != {True}, k++ ]; k]; Table[ a[n], {n, 0, 71}] (* Robert G. Wilson v *)
a(n) counts the nodes in generation n of the following tree. Generations 0..3 of the 6-convoluted tree are as follows; The path from the root is shown, with child nodes enclosed in []. GEN.0: [1]; GEN.1: 1->[6]; GEN.2: 1-6->[3,9,15,21,27,33]; GEN.3: 1-6-3->[2,8,14] 1-6-9->[2,8,14,20,26,32,38,44,50] 1-6-15->[2,8,14,20,26,32,38,44,50,56,62,68,74,80,86] 1-6-21->[2,8,14,20,26,32,38,44,50,56,62,68,74,80,86,92,98,104,110,116,122] 1-6-27->[2,8,14,20,26,32,38,44,50,56,62,68,74,80,86,92,98,104,110,116,122,128,134,140,146,152,158] 1-6-33->[2,8,14,20,26,32,38,44,50,56,62,68,74,80,86,92,98,104,110,116,122,128,134,140,146,152,158,164,170,176,182,188,194]. Each path in the tree from the root node forms the initial terms of a self-convolution 6th power of a sequence of integer terms.
a(2) = 12[3] + 21[3] = 110[3] = 12[10] where [b] indicates the basis b in which the number is written; a(3) = 123[4] + 231[4] + 312[4] = 126[10]; a(4) = 1234[5] + 2341[5] + 3412[5] + 4123[5] = 22220[5] = 1560[10],...
[((n + 1)^n - 1)*(n + 1) div 2: n in [1..20]]; // Vincenzo Librandi, Jan 09 2013
a:=proc(n) local b,m,i,s; b:=n+1: m:=add(i*b^(n-i),i=1..n): s:=m: for i to n-1 do m:=b^(n-1)*modp(m,b)+iquo(m,b): s:=s+m: od: s end; # or simply # a := n -> (n+1)/2*((n+1)^n-1)
Table[((n+1)^n-1)*(n+1)/2, {n,22}] (* Vladimir Joseph Stephan Orlovsky, Dec 28 2010 *)
a(1)=1, the sum of cyclic permutations of 1; a(2..4)=0,1,1 since 12 + 21 = 110 in base 3; a(5..8)=2,3,3,1 since 123 + 231 + 312 = 1332 in base 4; a(9..13)=0,2,2,2,2 since 1234 + 2341 + 3412 + 4123 = 22220 in base 5.
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