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A154958 Diagonal sums of number triangle A154957. 1
1, 1, 2, 1, 2, 1, 3, 2, 4, 2, 4, 2, 5, 3, 6, 3, 6, 3, 7, 4, 8, 4, 8, 4, 9, 5, 10, 5, 10, 5, 11, 6, 12, 6, 12, 6, 13, 7, 14, 7, 14, 7, 15, 8, 16, 8, 16, 8, 17, 9, 18, 9, 18, 9, 19, 10, 20, 10, 20, 10, 21, 11, 22, 11, 22, 11, 23, 12, 24, 12, 24, 12, 25, 13, 26, 13, 26, 13, 27, 14, 28, 14, 28 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

FORMULA

a(2n)=A004523(n+2); a(2n+1)=floor((n+3)/3)=A002264(n+3).

CROSSREFS

Sequence in context: A054065 A194868 A139024 * A025806 A025802 A139631

Adjacent sequences:  A154955 A154956 A154957 * A154959 A154960 A154961

KEYWORD

easy,nonn

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Jan 18 2009

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Last modified February 15 11:53 EST 2012. Contains 205778 sequences.