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A066047 Numbers n such that n divides A001045(n-1). 2
5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The preponderance of entries are primes. The first which is not prime is 341.

All composite entries are 2-pseudoprimes. - Charles R Greathouse IV, Nov 04 2016

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

a[0] = 0; a[1] = 1; a[n_] := a[n] = a[n - 1] + 2a[n - 2]; Select[ Range[500], IntegerQ[a[ # - 1]/# ] && # != 1 & ]

PROG

(PARI) is(n)=Mod(2, 3*n)^(n-1) == 1 \\ Charles R Greathouse IV, Nov 04 2016

CROSSREFS

Cf. A001045, A064739.

Sequence in context: A243292 A271116 A171525 * A140475 A171577 A215848

Adjacent sequences:  A066044 A066045 A066046 * A066048 A066049 A066050

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Dec 29 2001

EXTENSIONS

More terms from Robert G. Wilson v, Jan 03 2002

STATUS

approved

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Last modified January 25 16:42 EST 2020. Contains 331245 sequences. (Running on oeis4.)