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A191857 Second factor in happy factorization of n-th rhombic number. 6
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 (list; graph; refs; listen; history; text; internal format)
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. Reinhard Zumkeller, Oct 11 2015

STATUS

approved

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Last modified January 18 11:50 EST 2019. Contains 319271 sequences. (Running on oeis4.)