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A063957 Numbers not of the form round[m*sqrt(2)] for any integer m, i.e. complement of A022846. +0
1
2, 5, 9, 12, 15, 19, 22, 26, 29, 32, 36, 39, 43, 46, 50, 53, 56, 60, 63, 67, 70, 73, 77, 80, 84, 87, 90, 94, 97, 101, 104, 108, 111, 114, 118, 121, 125, 128, 131, 135, 138, 142, 145, 149, 152, 155, 159, 162, 166, 169, 172, 176, 179, 183, 186, 189, 193, 196, 200 (list; graph; listen)
OFFSET

1,1

COMMENT

Similar to Beatty sequences: where a pair of complementary Beatty sequences are floor[n*c] and floor[n*c/(c-1)] for c an irrational constant > 1, these pairs of complementary sequences are in general round[n*c] and round[(n-1/2)*c/(c-1)] for c an irrational constant > 1.

LINKS

Harry J. Smith, Table of n, a(n) for n=1,...,1000

FORMULA

a(n) =round[(n-1/2)*(2+sqrt(2))] =round[n*3.4142...-1.7071...]

EXAMPLE

round[m*sqrt(2)] starts 1,3,4,6,7,8,10,11,13,... so this sequence must start 2,5,9,12,...

PROGRAM

(PARI) { f=2 + sqrt(2); t=f/2; for (n=1, 1000, write("b063957.txt", n, " ", round(n*f - t)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 03 2009]

CROSSREFS

Cf. A001951, A001952, A007064, A022846. Consider natural numbers A000027 as a triangle 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc., then the a(n) indicate rows without a square.

Sequence in context: A057471 A099434 A108165 this_sequence A047385 A086814 A086343

Adjacent sequences: A063954 A063955 A063956 this_sequence A063958 A063959 A063960

KEYWORD

nonn

AUTHOR

Henry Bottomley (se16(AT)btinternet.com), Sep 04 2001

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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