A125727 - OEIS

A125727

a(1)=1. a(2)=2. a(n) = the smallest positive integer not occurring earlier in the sequence such that a(n-2)+a(n-1) is congruent to a(n) (mod n).

1, 2, 3, 5, 8, 7, 15, 6, 12, 18, 19, 13, 32, 17, 4, 21, 25, 10, 16, 26, 42, 24, 20, 44, 14, 58, 45, 47, 34, 51, 23, 74, 31, 37, 33, 70, 29, 61, 90, 71, 38, 67, 62, 41, 103, 52, 108, 64, 123, 87, 57, 40, 97, 83, 125, 96, 50, 30, 80, 110, 68, 54, 59, 49, 43, 92, 135, 91, 88, 39

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Ferenc Adorjan, Table of n,a(n) for n=1,10000

Ferenc Adorjan, Some characteristics of _Leroy Quet_'s permutation sequences

MATHEMATICA

f[l_List] := Block[{n = Length[l] + 1, k = Mod[ l[[ -1]] + l[[ -2]], n, 1]}, While[ MemberQ[l, k], k += n]; Append[l, k]]; Nest[f, {1, 2}, 70] (* Ray Chandler, Feb 03 2007 *)

PROG

(PARI){Quet_p4(n)=/* Permutation sequence a'la Leroy Quet, A125727 */local(x=[1, 2], k=0, w=3); for(i=3, n, if((k=(x[i-1]+x[i-2])%i)==0, k=i); while(bittest(w, k-1)>0, k+=i); x=concat(x, k); w+=2^(k-1)); return(x)}

CROSSREFS

Sequence in context: A121369 A284172 A230445 * A112337 A141804 A121368

Adjacent sequences: A125724 A125725 A125726 * A125728 A125729 A125730

KEYWORD

nonn

AUTHOR

Leroy Quet, Feb 02 2007

EXTENSIONS

Extended by Ray Chandler, Feb 03 2007

STATUS

approved