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A157936 Numbers n divisible by the least prime >= sqrt(n). 5
2, 4, 6, 9, 10, 15, 20, 25, 28, 35, 42, 49, 55, 66, 77, 88, 99, 110, 121, 130, 143, 156, 169, 170, 187, 204, 221, 238, 255, 272, 289, 304, 323, 342, 361, 368, 391, 414, 437, 460, 483, 506, 529, 551, 580, 609, 638, 667, 696, 725, 754, 783, 812, 841, 868, 899, 930 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Contains A001248, A006094 and A157937 as subsequences.

LINKS

Table of n, a(n) for n=1..57.

FORMULA

A157936 = A157937 union A001248

MATHEMATICA

dQ[n_]:=Module[{srn=Sqrt[n], x}, x=If [PrimeQ[srn], srn, NextPrime[srn]]; Divisible[n, x]]; Select [Range[1000], dQ]  (* Harvey P. Dale, Mar 12 2011 *)

PROG

(PARI) for( n=1, 1999, n % nextprime(sqrtint(n-1)+1) | print1(n", ")) /* sqrtint(n-1)+1 avoids rounding errors but can be replaced by sqrt(n) for small n */

CROSSREFS

Cf. A157942.

Sequence in context: A219787 A331006 A065388 * A184978 A333231 A227132

Adjacent sequences:  A157933 A157934 A157935 * A157937 A157938 A157939

KEYWORD

nonn

AUTHOR

M. F. Hasler, Mar 10 2009

STATUS

approved

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Last modified May 31 19:40 EDT 2020. Contains 334748 sequences. (Running on oeis4.)