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A031884 Smaller of a pair of consecutive lucky numbers with a gap of 2n. 3
1, 3, 15, 79, 141, 51, 787, 495, 171, 937, 903, 745, 2851, 1611, 1057, 3811, 5769, 4893, 8719, 10683, 9841, 24073, 9567, 28245, 25687, 3507, 26943, 35743, 44805, 51979, 64723, 23205, 50779, 51475, 264075, 155833, 238057, 178755, 143311, 400591 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) is the first occurrence of a difference of 2n between A000959(k+1) and A000959(k). - Robert G. Wilson v, May 12 2006

a(136) > 10^9. - Donovan Johnson, Dec 07 2011

Unknown terms a(166), a(176), a(178), a(182), and a(185) through a(209) are all greater than 10^10. - Kevin P. Thompson, Nov 24 2021

LINKS

Kevin P. Thompson, Table of n, a(n) for n = 1..165 (terms 1..135 from Donovan Johnson)

Kevin P. Thompson, Table of n, a(n) for n = 1..210 with unknown terms

EXAMPLE

a(4) = 79 since the lucky numbers A000959(20) = 79 and A000959(21) = 87 are the first consecutive pair with difference 2*4 = 8.

MATHEMATICA

lst = Range[1, 10^6, 2]; i = 2; While[ i <= (len = Length@lst) && (k = lst[[i]]) <= len, lst = Drop[lst, {k, len, k}]; i++ ]; f[n_] := Block[{k = 1}, While[t[[k + 1]] - t[[k]] != 2n, k++ ]; t[[k]]]; Array[f, 41] (* Robert G. Wilson v, May 12 2006 *)

CROSSREFS

Cf. A000959, A031885, A031883, A031158, A031886, A031888, A031890, A031892, A031894, A031896, A031898, A031900, A031902.

Sequence in context: A298771 A298576 A299568 * A337284 A186942 A193913

Adjacent sequences:  A031881 A031882 A031883 * A031885 A031886 A031887

KEYWORD

nonn,more,changed

AUTHOR

Patrick De Geest

EXTENSIONS

More terms from Robert G. Wilson v, May 12 2006

STATUS

approved

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Last modified November 28 13:47 EST 2021. Contains 349413 sequences. (Running on oeis4.)