A342979 a(1) = 2. For n > 1, a(n) is the smallest prime p > a(n-1) such that a(n-1) + p is a 4-almost prime (A014613).

2, 79, 131, 163, 167, 173, 191, 199, 263, 269, 277, 281, 283, 337, 349, 359, 367, 373, 397, 401, 419, 431, 439, 491, 521, 541, 557, 593, 599, 607, 613, 617, 619, 659, 677, 733, 751, 757, 761, 811, 857, 877, 907, 911, 919, 1009, 1021, 1039, 1051, 1097, 1129, 1163, 1181, 1237, 1279

Offset: 1

Author

Zak Seidov, Apr 02 2021

Keywords

• nonn

Comments

Minimal difference 2 occurs at positions 12, 32, 86, 118, 155, 242, 345, 427, 430, 517, .... E.g., 2 = 283 - 281 = 619 - 617 = 2083 - 2081.

Examples

			2 + 79 = 81 = A014613(8), 79 + 131 = 210 = A014613(27).
		

Crossrefs

Cf. A000040, A014613.

Programs

Mathematica

s = {2}; p = 2; Do[q = NextPrime[p]; While[4 != PrimeOmega[p + q], q = NextPrime[q]]; AppendTo[s, p = q], {55}]; s