A099520 a(1)=1; for n>1, a(n)=smallest integer m>0 not yet appearing in sequence such that m+a(n-1) is a multiple of n-1.

1, 2, 4, 5, 3, 7, 11, 10, 6, 12, 8, 14, 22, 17, 25, 20, 28, 23, 13, 44, 16, 26, 18, 51, 21, 29, 49, 32, 24, 34, 56, 37, 27, 39, 63, 42, 30, 81, 33, 45, 35, 47, 79, 50, 38, 52, 40, 54, 90, 57, 43, 59, 97, 9, 99, 66, 46, 68, 48, 70, 110, 73, 113, 76, 116, 144, 120, 148, 124, 83

Offset: 1

Author

Mark Hudson (mrmarkhudson(AT)hotmail.com), Oct 20 2004

Keywords

• easy
• nonn

Examples

			a(1)=1. a(2)=2 because a(2)+a(1)=2+1=3 which is a multiple of 1. Could not use a(2)=1 since 1 has already been used. a(3)=4 so that a(3)+a(2)=4+2=6 which is a multiple of 2, etc.
		

Crossrefs

Cf. A099506 for similar sequence with a(n)+a(n-1)=multiple of n.