|
|
A097446
|
|
Concatenate consecutive prime-sided isosceles triangles.
|
|
0
|
|
|
233, 355, 577, 71111, 111313, 131717, 171919, 192323, 232929, 293131, 313737, 374141, 414343, 434747, 475353, 535959, 596161, 616767, 677171, 717373, 737979, 798383, 838989, 899797, 97101101, 101103103, 103107107, 107109109, 109113113
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
2,1
|
|
LINKS
|
|
|
FORMULA
|
Consider triangles with sides (2, 3, 3), (3, 5, 5), .., (x, y, y) where x is prime and y is the next prime after x. Concatenate these sides for output.
|
|
EXAMPLE
|
For side x = 7, y = 11 to get concatenate 71111.
|
|
MATHEMATICA
|
con[a_, b_]:=FromDigits[Join[IntegerDigits[a], IntegerDigits[b], IntegerDigits[ b]]]; con@@@Partition[Prime[Range[50]], 2, 1] (* Harvey P. Dale, Jul 25 2011 *)
|
|
PROG
|
(PARI) f(n) = for(x=1, n, y=Str(prime(x)); y=concat(y, concat(Str(prime(x+1)), Str(prime (x+1)))); print1(y", "))
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|