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A062016
Numbers with all odd digits which can be factored into two numbers > 1 with odd digits.
2
9, 15, 33, 35, 39, 51, 55, 57, 75, 77, 91, 93, 95, 99, 111, 117, 119, 133, 135, 153, 155, 159, 171, 175, 177, 195, 315, 333, 339, 351, 355, 357, 371, 375, 393, 395, 399, 511, 513, 519, 531, 537, 539, 553, 555, 573, 575, 579, 591, 595, 597, 711, 715, 755, 775, 777, 791, 795, 917, 931, 933, 935, 939, 951, 955, 957, 959, 973, 975
OFFSET
1,1
LINKS
EXAMPLE
95 = 19*5 is OK but 115 = 23*5 and 17*5 = 85 are not.
MAPLE
dmax:= 4: # to get all terms of up to dmax digits
S[1]:= [1, 3, 5, 7, 9]:
for d from 2 to dmax do
S[d]:= map(t -> seq(10*t+j, j=1..9, 2), S[d-1])
od:
T:= {seq(op(S[i]), i=1..dmax)} minus {1}:
R:= T intersect {seq(seq(T[i]*T[j], j=1..i), i=1..nops(T))}:
sort(convert(R, list)); # Robert Israel, Nov 22 2016
CROSSREFS
Sequence in context: A103508 A051246 A320062 * A108637 A091296 A107076
KEYWORD
nonn,base,easy
AUTHOR
Amarnath Murthy, Jun 01 2001
EXTENSIONS
More terms from Matthew Conroy, Jun 11 2001
Offset corrected by and more terms from Matthew House, Nov 22 2016
STATUS
approved