A125772 Primes not of the form j*T_k +/- 1, where T_k is the k-th triangular number greater than 9.
2, 3, 5, 7, 13, 17, 23, 47, 53, 97, 103, 163, 173, 193, 227, 257, 283, 317, 347, 353, 367, 373, 383, 443, 457, 487, 523, 557, 563, 607, 653, 677, 733, 743, 773, 787, 823, 853, 877, 887, 907, 977, 983, 997, 1033, 1097, 1163, 1193, 1213, 1237, 1277, 1283, 1307
Offset: 1
Keywords
Examples
17 is not of the form j*T_k +/- 1 for any j = 1 or 2 and the triangular numbers, 10, 15 or 21.
Crossrefs
Cf. Complement of A125771.
Programs
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Mathematica
s = {}; Do[m = j*k*(k + 1)/2; If[PrimeQ[m - 1], AppendTo[s, m - 1]]; If[PrimeQ[m + 1], AppendTo[s, m + 1]], {j, 140}, {k, 4, 43}]; Complement[ Prime@ Range@220, Take[Union@s, 200]]
Comments