OFFSET

1,1

COMMENTS

Numbers that are the sum of two terms of A001043, but not sum of a different pair of two terms.

EXAMPLE

Recall that A001043 begins with 5,8,12,18,24,30,36,42,52,60,68,78,84,90, ...

So 48 is not in the sequence because 48 = 18+30 = 24+24.

But 88 is in the sequence as it is only = 52+36.

And 89 is there too because = 84+5.

PROG

(PARI) issum(i, vss) = {nb = 0; for (j = 1, #vss, if (vss[j] > i, break); for (k = 1, j, sv = vss[j] + vss[k]; if (sv == i, nb++); if (sv > i, break); ); ); return (nb == 1); }

lista(nn) = {vec = vector(nn, i, i); vss = select(i->((precprime((i-1)/2) + nextprime(i/2) == i) && (i>2)), vec); for (i = 1, nn, if (issum(i, vss), print1(i, ", ")); ); } \\ Michel Marcus, Oct 14 2013

CROSSREFS

KEYWORD

nonn

AUTHOR

Zak Seidov, Feb 15 2008

EXTENSIONS

Example, corrected and extended by Michel Marcus, Oct 14 2013

STATUS

approved