|
| |
|
|
A066042
|
|
n divided by (sum of digits of n times product of digits of n) is prime.
|
|
2
| |
|
|
12, 111, 216, 432, 41112, 81216, 186624, 248832, 311472, 316224, 341712, 422144, 714112, 1131111, 1131732, 1191915, 1211328, 1292112, 1418112, 2192832, 3112128, 4331232, 11127424, 11311272, 18122112, 21111192, 26726112, 28422144, 34338816
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
LINKS
| Harry J. Smith, Table of n, a(n) for n=1,...,54
|
|
|
FORMULA
| Sum digits of n; take product of digits of n; multiply sum by product and divide into n. If prime, add to sequence.
|
|
|
EXAMPLE
| a(2)=111 because 1+1+1=3 and 1*1*1=1 and 3*1=3 and 111/3=37 and 37 is prime.
|
|
|
PROG
| (PARI) ProdD(x)= { local(p=1); while (x>9 && p>0, p*=x%10; x\=10); return(p*x) } SumD(x)= { local(s=0); while (x>9, s+=x%10; x\=10); return(s + x) } { n=0; for (m=1, 10^12, p=ProdD(m); if (p == 0, next); f=m/(SumD(m)*p); if (frac(f)==0 && isprime(f), write("b066042.txt", n++, " ", m); if (n==100, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Nov 08 2009]
|
|
|
CROSSREFS
| Cf. A038369, A049102, A066146.
Sequence in context: A049102 A075231 A085773 * A153597 A036733 A123933
Adjacent sequences: A066039 A066040 A066041 * A066043 A066044 A066045
|
|
|
KEYWORD
| easy,nonn,base
|
|
|
AUTHOR
| Enoch Haga (Enokh(AT)comcast.net), Dec 13 2001
|
|
|
EXTENSIONS
| Checked to over 10^8 (110,508,539) without finding another example.
EXAMPLE corrected and OFFSET changed from 12,1 to 1,1 by Harry J. Smith (hjsmithh(AT)sbcglobal.net), Nov 08 2009
Should have found 34338816, 37121112, and 41174112 < 10^8. Term a(29) from Harry J. Smith (hjsmithh(AT)sbcglobal.net), Nov 08 2009
|
| |
|
|
