A254100 Postludic numbers: Second column of Ludic array A255127.

4, 9, 19, 31, 55, 73, 101, 145, 167, 205, 253, 293, 317, 355, 413, 473, 521, 569, 623, 677, 737, 763, 833, 917, 983, 1027, 1051, 1121, 1171, 1273, 1337, 1411, 1471, 1571, 1619, 1663, 1681, 1807, 1957, 1991, 2087, 2113, 2171, 2245, 2275, 2335, 2401, 2497, 2593, 2713, 2771, 2831, 2977, 3047, 3113

Offset: 1

Author

Antti Karttunen, Feb 22 2015

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10001

Crossrefs

Column 2 of A255127. (Row 2 of A255129). Positions of 2's in A260739.

Subsequence of A192607, A302036 and A302038.

Cf. A276576, A276606 (first differences).

Cf. also A001248, A219178.

Programs

Mathematica

rows = 100; cols = 2; t = Range[2, 10^4]; r = {1}; n = 1; While[n <= rows, k = First[t]; AppendTo[r, k]; t0 = t; t = Drop[t, {1, -1, k}]; ro[n++] = Complement[t0, t][[1 ;; cols]]]; A = Array[ro, rows]; Table[A[[n, 2]], {n, 1, rows} ] (* Jean-François Alcover, Mar 14 2016, after Ray Chandler *)

Scheme

(define (A254100 n) (A255127bi n 2)) ;; A255127bi given in A255127.

Formula

a(n) = A255407(A001248(n)).