OFFSET
1,1
COMMENTS
All the palindromic numbers in base 7 with an even number of digits belong to the sequence.
Here the fulcrum is between two digits while in the sequence from A282107 to A282115 is one of the digits.
The first number with this property in all the bases from 2 to 7 is
86964945. - Giovanni Resta, Feb 15 2017
LINKS
Paolo P. Lava, Table of n, a(n) for n = 1..10000
EXAMPLE
641 in base 7 is 1604. If we split the number in 16 and 04 we have 6*1 + 1*2 = 8 for the left side and 0*1 + 4*2 = 8 for the right one.
MAPLE
P:=proc(n, h) local a, j, k: a:=convert(n, base, h):
for k from 1 to nops(a)-1 do
if add(a[j]*(k-j+1), j=1..k)=add(a[j]*(j-k), j=k+1..nops(a))
then RETURN(n); break: fi: od: end: seq(P(i, 7), i=1..10^3);
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Paolo P. Lava, Feb 15 2017
STATUS
approved