A210455 Characteristic function of pseudoperfect (or semiperfect) numbers.

0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0

Offset

1

Comments

a(A005835(n)) = 1 and a(A136447(n)) = 0.

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Semiperfect Number

Wikipedia, Semiperfect number

Index entries for characteristic functions

Prog

(Haskell)
a210455 n = fromEnum $ p (a027751_row n) n where
   p ks m = m == 0 || not (null ks) && head ks <= m &&
            (p (tail ks) (m - head ks) || p (tail ks) m)

Crossrefs

Cf. A027751.

Sequence in context: A093958 A044936 A133944 * A294936 A378539 A296210

Adjacent sequences: A210452 A210453 A210454 * A210456 A210457 A210458

Keyword

nonn

Author

Reinhard Zumkeller, Jan 21 2013

Status

approved