A038570 Second derivative of n.

0, 0, 0, 0, 1, 0, 0, 0, 2, 3, 0, 1, 1, 0, 0, 0, 4, 5, 6, 7, 1, 0, 3, 2, 2, 3, 0, 1, 1, 0, 0, 0, 8, 9, 10, 11, 13, 12, 15, 14, 2, 3, 0, 1, 7, 6, 5, 4, 4, 5, 6, 7, 1, 0, 3, 2, 2, 3, 0, 1, 1, 0, 0, 0, 16, 17, 18, 19, 21, 20, 23, 22, 26, 27, 24, 25, 31, 30, 29, 28, 4, 5, 6, 7, 1, 0, 3, 2, 14, 15, 12

Offset

0,9

Comments

a(n) = A038554(A038554(n)). - Reinhard Zumkeller, Mar 06 2013

Links

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Mathematica

dtn[ L_ ] := Fold[ 2#1+#2&, 0, L ]; f[ n_ ] := dtn[ Map[ Abs[ #[ [ 1 ] ]-#[ [ 2 ] ] ]&, Partition[ IntegerDigits[ n, 2 ], 2, 1 ] ] ]; Table[ f[ f[ n ] ], {n, 0, 120} ]

Prog

(Haskell)
a038570 = a038554 . fromIntegral . a038554
-- Reinhard Zumkeller, Mar 06 2013

Crossrefs

Cf. A038554.

Sequence in context: A229615 A359177 A135814 * A306559 A103498 A030386

Adjacent sequences: A038567 A038568 A038569 * A038571 A038572 A038573

Keyword

nonn,easy,nice,look

Author

N. J. A. Sloane

Extensions

More terms from Erich Friedman

Status

approved