A117311 Beginning with sequence A096903, choose only those rows such that when a(n) is in factored form all exponents of a(n) are consecutive starting at 1.

2, 6, 12, 18, 30, 60, 90, 150, 180, 300, 450, 210, 360, 540, 600, 1350, 1500, 2250, 420, 630, 1050, 1470, 1260, 2100, 2940, 3150, 4410, 7350, 2310, 2520, 3780, 4200, 5880, 9450, 10500, 13230, 15750, 20580, 30870, 36750, 51450, 4620, 6930, 11550, 16170

Offset

1,1

Comments

Included rows can be mapped to permutation groups; e.g. - (12,18) to C2; (60,90,150) and (180,300,450) to C3; (360,540,600,1350,1500,2250) to S3; and (420,630,1050,1470) to C4.

Links

Table of n, a(n) for n=1..45.

Example

10 is not a member of a(n) since it is not a term in A096903.
24 is not a member of a(n) since 24 = 2^3 * 3^1 and exponents 1 & 3 are not consecutive.
12, 60 and 180 are included since the exponents are (2,1), (2,1,1) & (2,2,1) respectively.

Crossrefs

Cf. A055932 A084918 A096903.

Sequence in context: A181660 A036913 A317089 * A125024 A178480 A053660

Adjacent sequences: A117308 A117309 A117310 * A117312 A117313 A117314

Keyword

nonn,tabf

Author

Alford Arnold, Mar 07 2006

Extensions

More terms from Franklin T. Adams-Watters, Nov 20 2006

Status

approved