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A098837 Smith semiprimes. 1
4, 22, 58, 85, 94, 121, 166, 202, 265, 274, 319, 346, 355, 382, 391, 454, 517, 526, 535, 562, 634, 706, 778, 895, 913, 922, 958, 985, 1111, 1165, 1219, 1255, 1282, 1507, 1633, 1642, 1678, 1795, 1822, 1858, 1894, 1903, 1921, 1966, 2038, 2155, 2173, 2182, 2218 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Cubefree Smith numbers. This is to cubefree as A202387 is to squarefree. [Jonathan Vos Post, Jan 02 2012]
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
FORMULA
A006753 INTERSECTION A004709.
EXAMPLE
a(3)=58 because 58 is a Smith number as well as a semiprime.
MATHEMATICA
sspQ[n_]:=PrimeOmega[n]==2&&Total[Flatten[IntegerDigits/@(Table[#[[1]], #[[2]]]&/@FactorInteger[n])]]==Total[IntegerDigits[n]]; Select[Range[ 2220], sspQ] (* Harvey P. Dale, Jul 25 2019 *)
PROG
(PARI) dsum(n)=my(s); while(n, s+=n%10; n\=10); s
list(lim)=my(v=List(), d); forprime(p=2, sqrt(lim), d=dsum(p); forprime(q=p, lim\p, if(d+dsum(q)==dsum(p*q), listput(v, p*q)))); vecsort(Vec(v)) \\ Charles R Greathouse IV, Jan 03 2012
CROSSREFS
Sequence in context: A341375 A076525 A089761 * A104171 A036924 A130015
KEYWORD
base,nonn
AUTHOR
Shyam Sunder Gupta, Oct 10 2004
STATUS
approved

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Last modified February 21 04:30 EST 2024. Contains 370219 sequences. (Running on oeis4.)