A099072 First differences of A000960, divided by 2.

1, 2, 3, 3, 4, 6, 5, 7, 8, 6, 9, 12, 7, 17, 13, 8, 15, 18, 9, 21, 19, 6, 30, 11, 24, 19, 23, 18, 30, 27, 22, 18, 42, 11, 30, 42, 9, 39, 36, 30, 19, 56, 6, 48, 57, 13, 44, 46, 17, 45, 69, 13, 41, 49, 56, 27, 85, 18, 30, 84, 26, 64, 26, 64, 47, 54, 45, 94, 17, 36, 85, 60, 23, 79, 98

Offset: 1

Author

N. J. A. Sloane, Nov 15 2004

Keywords

• nonn
• easy

Crossrefs

Cf. A000960, A056526.

Programs

Mathematica

del[lst_, k_] := lst[[ Select[ Range[ Length[ lst]], Mod[ #, k] != 0 &]]]; For[ k = 2; s = Range[10000], k <= Length[s], k++, s = del[s, k]]; (Drop[s, 1] - Drop[s, -1])/2

Formula

a(n) = A073359(n+1) - A073359(n), (conjectured, n>1). - Bill McEachen, Dec 22 2024

Extensions

More terms from Robert G. Wilson v, Nov 15 2004