

A085491


Number of ways to write n as sum of distinct divisors of n+1.


5



1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 5, 0, 0, 0, 1, 0, 3, 0, 1, 0, 0, 0, 5, 0, 0, 0, 3, 0, 2, 0, 0, 0, 0, 0, 10, 0, 0, 0, 0, 0, 1, 0, 2, 0, 0, 0, 31, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 26, 0, 0, 0, 0, 0, 1, 0, 6, 0, 0, 0, 23, 0, 0, 0, 1, 0, 20, 0, 0, 0, 0, 0, 21, 0, 0, 0, 1
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OFFSET

0,12


COMMENTS

a(A085492(n)) = 0; a(A085493(n)) > 0; a(A085494(n)) = 1.


LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..10000


EXAMPLE

n=11, divisors of 12=11+1 that are not greater 11: {1,2,3,4,6}, 11=6+5=6+4+1, therefore a(11)=2.


MAPLE

a:= proc(m) option remember; local b, l; b, l:=
proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
b(n, i1)+`if`(l[i]>n, 0, b(nl[i], i1))))
end, sort([numtheory[divisors](m+1)[]]);
forget(b); b(m, nops(l)1)
end:
seq(a(n), n=0..120); # Alois P. Heinz, Mar 12 2019


MATHEMATICA

a[n_] := Module[{dd}, dd = Select[Divisors[n+1], # <= n&]; Select[ IntegerPartitions[n, dd // Length, dd], Reverse[#] == Union[#]&] // Length]; Array[a, 100, 0] (* JeanFrançois Alcover, Mar 12 2019 *)


CROSSREFS

Cf. A085496.
Sequence in context: A280751 A280749 A321936 * A321013 A284258 A322389
Adjacent sequences: A085488 A085489 A085490 * A085492 A085493 A085494


KEYWORD

nonn


AUTHOR

Reinhard Zumkeller, Jul 03 2003


EXTENSIONS

a(0)=1 prepended by Alois P. Heinz, Mar 12 2019


STATUS

approved



