A191857 Second factor in happy factorization of n-th rhombic number.

3, 1, 4, 11, 5, 19, 1, 6, 27, 1, 2, 7, 20, 43, 1, 8, 51, 59, 9, 67, 1, 3, 1, 10, 83, 29, 22, 7, 2, 11, 1, 52, 107, 23, 1, 12, 123, 1, 2, 131, 5, 4, 139, 13, 1, 38, 53, 2, 163, 1, 14, 171, 25, 8, 179, 187, 1, 2, 15, 1, 100, 26, 211, 5, 54, 3, 1, 16, 227, 77

Offset

1,1

Comments

a(n) = A007967(A007970(n)) = A007970(n) / A191856(n);

(A191856(n), a(n)) is a 2-happy couple;

notation: E in the Conway link.

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..99

J. H. Conway, On Happy Factorizations, J. Integer Sequences, Vol. 1, 1998, #1.

Prog

(Haskell)
a191857 = a007967 . a007970  -- Reinhard Zumkeller, Oct 11 2015

Crossrefs

Cf. A007967, A007970, A191856.

Sequence in context: A125077 A065253 A010756 * A248044 A153278 A010284

Adjacent sequences: A191854 A191855 A191856 * A191858 A191859 A191860

Keyword

nonn

Author

Reinhard Zumkeller, Jun 18 2011

Extensions

Wrong formula removed (thanks to Wolfdieter Lang, who pointed this out), by Reinhard Zumkeller, Oct 11 2015

Status

approved