A282108 - OEIS

A282108

Numbers n with k digits in base x (MSD(n)=d_k, LSD(n)=d_1) such that, chosen one of their digits in position d_k < j < d_1, is Sum_{i=j+1..k}{(i-j)*d_i} = Sum_{i=1..j-1}{(j-i)*d_i}. Case x = 3.

10, 13, 16, 20, 23, 26, 29, 30, 32, 35, 39, 48, 55, 60, 64, 69, 73, 78, 82, 87, 90, 91, 96, 100, 105, 112, 117, 121, 130, 137, 142, 144, 146, 151, 155, 160, 164, 165, 169, 173, 178, 180, 182, 187, 192, 194, 203, 207, 212, 219, 224, 233, 234, 242, 246, 247, 256

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OFFSET

1,1

COMMENTS

All the palindromic numbers in base 3 with an odd number of digits belong to the sequence.

Here the fulcrum is one of the digits while in the sequence from A282143 to A282151 is between two digits.

LINKS

Paolo P. Lava, Table of n, a(n) for n = 1..10000

EXAMPLE

35 in base 3 is 1022. If j = 2 (second 2 from the right) we have 0*1 + 1*2 = 2 for the left side and 2*1 for the right one.

MAPLE

P:=proc(n, h) local a, j, k: a:=convert(n, base, h):