A102070 Numbers that can be expressed as p+p^n (p prime, n >= 0) in more than one way.

4, 6, 10, 12, 14, 18, 30, 34, 38, 62, 74, 84, 130, 132, 158, 182, 194, 258, 278, 314, 350, 380, 398, 422, 458, 514, 542, 614, 662, 674, 734, 758, 878, 992, 998, 1094, 1154, 1202, 1214, 1238, 1322, 1382, 1454, 1622, 1658, 1722, 1754, 1874, 1934, 1994, 2018, 2138

Offset

1,1

Links

Table of n, a(n) for n=1..52.

Example

14 = 7+7^1 = 13+13^0. 130 = 2+2^7 = 5+5^3.

Prog

(PARI) v = vector(20000); count = 0; i = 1; p = 2; while (p < 5000, pow = 1; while (pow < 5000, n = p + pow; count++; v[count] = n; pow *= p); i++; p = prime(i)); w = vector(count, x, v[x]); v = vecsort(w); i = 3; for (j = 2, count, if (v[j] == v[j - 1] && v[j] != v[j - 2], print(v[j])));

Crossrefs

Sequence in context: A284883 A134333 A114331 * A026402 A036438 A338519

Adjacent sequences: A102067 A102068 A102069 * A102071 A102072 A102073

Keyword

easy,nonn

Author

David Wasserman, Dec 28 2004

Status

approved