login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A080672 Numbers having divisors 2 or 3 or 5 or 7. 4
2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 60, 62, 63, 64, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A020639(a(n)) <= 7; A210679(a(n)) > 0. - Reinhard Zumkeller, Apr 02 2012

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Index entries for linear recurrences with constant coefficients, order 162.

FORMULA

a(n) = a(n-162). - Charles R Greathouse IV, Sep 14 2015

a(n) = 35n/27 + O(1). - Charles R Greathouse IV, Sep 14 2015

PROG

(PARI) div2357(n)= for(x=1, n, if(gcd(x, 210)<>1, print1(x" ")) )

(PARI) is(n)=gcd(n, 210)>1 \\ Charles R Greathouse IV, Sep 14 2015

(Haskell)

a080672 n = a080672_list !! (n-1)

a080672_list = filter ((<= 7) . a020639) [2..]

-- Reinhard Zumkeller, Apr 02 2012

CROSSREFS

Cf. A020639, A008364 (complement), A002473 (subsequence).

Sequence in context: A247805 A164713 A070331 * A056757 A225737 A079333

Adjacent sequences:  A080669 A080670 A080671 * A080673 A080674 A080675

KEYWORD

easy,nonn

AUTHOR

Cino Hilliard, Mar 02 2003

EXTENSIONS

Offset fixed by Reinhard Zumkeller, Apr 02 2012

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 6 11:51 EDT 2020. Contains 333273 sequences. (Running on oeis4.)