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A183217 Complement of the pentagonal numbers. 3
2, 3, 4, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 93 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..85.

FORMULA

a(n)= n+Floor[1/2+(2n/3)^(1/2)].

EXAMPLE

The pentagonal numbers:  A000326=(1,5,12,22,35,...), so that A183217=(2,3,4,6,7,8,9,10,11,13,14,...).

MATHEMATICA

Table[n+Floor[1/2+(2n/3)^(1/2)], {n, 100}]

CROSSREFS

Cf. A000326.

Sequence in context: A048263 A141451 A285211 * A047303 A057906 A039214

Adjacent sequences:  A183214 A183215 A183216 * A183218 A183219 A183220

KEYWORD

nonn

AUTHOR

Clark Kimberling, Jan 01 2011

STATUS

approved

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Last modified May 12 21:06 EDT 2021. Contains 343829 sequences. (Running on oeis4.)