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A135372 Highly composite numbers + 1. 0
2, 3, 5, 7, 13, 25, 37, 49, 61, 121, 181, 241, 361, 721, 841, 1261, 1681, 2521, 5041, 7561, 10081, 15121, 20161, 25201, 27721, 45361, 50401, 55441, 83161, 110881, 166321, 221761, 277201, 332641, 498961, 554401, 665281, 720721, 1081081 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) prime for n = 1, 2, 3, 4, 5, 7, 9, 11, 12, 18, 20, 22, 23, 26, 28, 30, 34, 35, ... a(n) square of prime for n = 6, 8, 10, 13, 15, 17, 19, ... a(n) is not a prime power for n = 14 (semiprime), 16 (semiprime), 21 (semiprime), 24 (3-almost prime), 25 (semiprime), 27 (semiprime), 29 (semiprime), 31 (semiprime), 32 (semiprime), 33 (semiprime), 36 (semiprime), 37 (semiprime), 38 (semiprime), 39 (3-almost prime), 40 (semiprime), 41 (semiprime).

LINKS

Table of n, a(n) for n=1..39.

FORMULA

a(n) = A002182(n)+1.

CROSSREFS

Cf. A000040, A001248, A002182.

Sequence in context: A124147 A227627 A335116 * A037021 A114741 A096177

Adjacent sequences:  A135369 A135370 A135371 * A135373 A135374 A135375

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post, Dec 09 2007

STATUS

approved

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Last modified April 15 00:13 EDT 2021. Contains 342971 sequences. (Running on oeis4.)