A083510 Members of A000124 which are the arithmetic mean of two other members.
4, 22, 29, 37, 79, 106, 154, 172, 191, 211, 254, 326, 352, 379, 466, 529, 667, 704, 904, 947, 991, 1036, 1129, 1177, 1276, 1379, 1486, 1541, 1597, 1654, 1712, 1771, 1892, 1954, 2279, 2347, 2557, 2629, 2776, 2927, 3004, 3082, 3161, 3404, 3571, 3742, 3829
Offset: 1
Keywords
Examples
4 = (1+7)/2, 37 = (7 +67)/2. etc.
Crossrefs
Cf. A000124.
Programs
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PARI
V = vector(5000); for (i = 1, 5000, V[i] = 1 + binomial(i, 2)); count = 0; i = 1; while (count < 50, i++; found = 0; j = i - 1; k = i + 1; x = 2*V[i]; while (!found && j, if (V[j] + V[k] > x, j--, if (V[j] + V[k] < x, k++, found = 1))); if (found, count++; print1(V[i], ", "))); \\ David Wasserman, Nov 18 2004
Extensions
Corrected and extended by David Wasserman, Nov 18 2004