OFFSET
0,2
COMMENTS
n such that there exists a permutation p_1, ..., p_n of 1, ..., n such that i + p_i is a power of 10 for every i.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..10000
FORMULA
a(n) = 9*A007088(n).
a(2n) = 10*a(n), a(2n+1) = a(2n)+9.
MAPLE
A097256:=n->(9/2) * add((1-(-1)^floor(n/2^i))*10^i, i=0..n); seq(A097256(n), n=0..30); # Wesley Ivan Hurt, Feb 11 2014
MATHEMATICA
Table[(9/2) Sum[(1 - (-1)^Floor[n/2^i]) 10^i, {i, 0, n}], {n, 0, 30}] (* Wesley Ivan Hurt, Feb 11 2014 *)
PROG
(Haskell)
a097256 n = a097256_list !! n
a097256_list = map (* 9) a007088_list
-- Reinhard Zumkeller, Jan 10 2012
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Ray Chandler, Aug 03 2004
STATUS
approved