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A109825 Initial terms of groups in the partition of the sequence of natural numbers A109411. 3
1, 4, 5, 9, 10, 11, 16, 18, 21, 22, 23, 36, 39, 40, 43, 45, 47, 49, 50, 54, 60, 62, 63, 69, 70, 72, 74, 75, 89, 93, 94, 95, 96, 99, 104, 106, 107, 109, 111, 112, 115, 116, 126, 128, 135, 140, 144, 146, 147, 149, 151, 153, 159, 160, 162, 165, 170, 172, 175, 179, 184, 190 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..62.

MATHEMATICA

s={1}; a=1; Do[Do[If[Plus@@Last/@FactorInteger[(a+x)(x-a+1)/2]==2, a=x+1; AppendTo[s, a]; Break[]], {x, a, 20000}], {k, 1, 100}]; A109825=s

CROSSREFS

Cf. A109411, A109826.

Sequence in context: A007536 A209887 A064801 * A327175 A193259 A008935

Adjacent sequences:  A109822 A109823 A109824 * A109826 A109827 A109828

KEYWORD

nonn

AUTHOR

Zak Seidov, Jul 03 2005

STATUS

approved

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Last modified August 7 21:39 EDT 2022. Contains 355995 sequences. (Running on oeis4.)