A031886 -id:A031886 - cp's OEIS frontend

A031884 Smaller of a pair of consecutive lucky numbers with a gap of 2n.

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, 223095, 181581, 466813

Offset: 1

Patrick De Geest

nonn

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

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

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

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

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 *)

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

A128539 Lucky numbers with size of gaps equal to 6 (lower terms).

Original entry on oeis.org

1, 3, 7, 9, 15, 25, 31, 37, 43, 63, 67, 69, 73, 87, 93, 99, 105, 127, 129, 135, 163, 189, 195, 205, 231, 235, 261, 267, 283, 297, 321, 361, 385, 393, 409, 415, 421, 427, 477, 483, 489, 511, 529, 535, 553, 577, 613, 615, 639, 645, 673, 679, 693, 717, 723, 729

Offset: 1

Jonathan Vos Post, May 08 2007

This is to (A031886) Lucky numbers with size of gaps equal to 4 (lower terms) as (A023201) smaller member of sexy prime pairs are to (A023200) smaller member p of cousin prime pairs.

Supersequence of A031888. [From R. J. Mathar, Oct 22 2010]

Cf. A000959, A023200, A023201, A031886.

{L in A000959 such that L+6 in A000959}.

More terms from R. J. Mathar, Oct 22 2010

cp's OEIS Frontend

A031884 Smaller of a pair of consecutive lucky numbers with a gap of 2n.

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