

A155740


Odd numbers that are the concatenation of a prime p and the pth nonprime nonnegative integer.


1



21, 1725, 1927, 2333, 3751, 79105, 83111, 131169, 167213, 173219, 191243, 193245, 197249, 227287, 229289, 251315, 269335, 307381, 317393, 367453, 379469, 383473, 397489, 419515, 421517, 431529, 433531, 439537, 449549, 463565, 499609, 521635
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OFFSET

1,1


LINKS



EXAMPLE

21 is a term because it is the concatenation of 2 (a prime) and the 2nd nonnegative nonprime integer 1 (which is odd);
1725 is a term because it is the concatenation of 17 (a prime) and the 17th nonnegative nonprime integer 25 (which is odd).


MAPLE

cat2 := proc(a, b) dgsb := max(1, ilog10(b)+1) ; a*10^dgsb+b ; end proc:
A155740 := proc(n) p := ithprime(n) ; c := A141468(p) ; if type(c, 'odd') then cat2(p, c) ; printf("%d, ", %) ; end if; return ; end proc:


CROSSREFS



KEYWORD

nonn,base,less


AUTHOR



EXTENSIONS

Corrected (1321 removed, all terms >= 200000 corrected) by R. J. Mathar, May 15 2010


STATUS

approved



