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A278999 Numbers of the form (5h+2)*5^k-1 or (5h+3)*5^k-1 for h,k in N. 2
1, 2, 6, 7, 9, 11, 12, 14, 16, 17, 21, 22, 26, 27, 31, 32, 34, 36, 37, 39, 41, 42, 46, 47, 49, 51, 52, 56, 57, 59, 61, 62, 64, 66, 67, 71, 72, 74, 76, 77, 81, 82, 84, 86, 87, 89, 91, 92, 96, 97, 101, 102, 106, 107, 109, 111, 112, 114, 116, 117, 121, 122, 126, 127, 131 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Ray Chandler, Table of n, a(n) for n = 1..10000

Hao Fu, G.-N. Han, Computer assisted proof for Apwenian sequences related to Hankel determinants, arXiv preprint arXiv:1601.04370 [math.NT], 2016. See sequence "K" in Section 2.2.

MATHEMATICA

isok[n_]:=Module[{ord=IntegerExponent[n+1, 5]}, MemberQ[{2, 3}, Mod[(n+1)/5^ord, 5]]]; Select[Range[0, 131], isok] (*Ray Chandler, Dec 17 2016*)

CROSSREFS

Complement of A278998.

Sequence in context: A047554 A206446 A079335 * A190784 A061416 A190247

Adjacent sequences:  A278996 A278997 A278998 * A279000 A279001 A279002

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 07 2016

EXTENSIONS

More terms from Ray Chandler, Dec 17 2016

STATUS

approved

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Last modified October 17 13:57 EDT 2019. Contains 328113 sequences. (Running on oeis4.)