A116538 - OEIS

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A116538

a(1)=1, a(2)=2; a(n) is the smallest positive integer not occurring earlier in the sequence such that gcd(a(n-2), a(n-1)+a(n)) = 1.

1, 2, 3, 4, 6, 5, 8, 9, 10, 7, 12, 11, 14, 13, 16, 15, 18, 19, 22, 17, 20, 21, 26, 24, 23, 30, 25, 28, 29, 32, 27, 34, 31, 36, 33, 38, 35, 40, 39, 42, 37, 46, 41, 44, 43, 48, 45, 50, 47, 52, 49, 54, 53, 56, 51, 58, 55, 60, 57, 62, 59, 64, 61, 66, 63, 68, 69, 70, 67, 72, 65, 74

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

OFFSET

1,2

COMMENTS

Sequence may be a permutation of the positive integers.

LINKS

Diana Mecum, Table of n, a(n) for n = 1..1132

EXAMPLE

Among the positive integers not occurring among the first 6 terms of the sequence, 8 is the smallest m such that gcd(a(5), a(6)+m) = gcd(6,5+m) = 1.

Had we used 7 for m instead, we would have had gcd(6,5+7) = 6. So a(7) = 8.

CROSSREFS

Sequence in context: A183090 A232559 A094138 * A084287 A263265 A263267

Adjacent sequences: A116535 A116536 A116537 * A116539 A116540 A116541

KEYWORD

nonn

AUTHOR

Leroy Quet, Mar 27 2006

EXTENSIONS

More terms from Diana L. Mecum, Jun 21 2007

STATUS

approved