A138042 Numbers k such that A096379(k)=A096379(k+1).
2, 7, 13, 19, 49, 69, 116, 182, 206, 225, 229, 236, 253, 265, 288, 315, 324, 352, 379, 390, 394, 435, 492, 497, 542, 551, 567, 625, 643, 658, 718, 754, 794, 920, 930, 935, 958, 966, 988, 1025, 1032, 1085, 1101, 1128, 1155, 1171, 1173, 1225, 1235, 1249
Offset: 1
Keywords
Examples
n=2: {prime(n), 2*prime(n+2)-prime(n+3)}={3,2*7-11},
n=7: {prime(7), 2*prime(9)-prime(10)}={17,2*23-29},
n=13: {prime(13), 2*prime(15)-prime(16)}={41,2*47-53},
n=19: {prime(19), 2*prime(21)-prime(22)}={67,2*73-79}.
Links
- Zak Seidov, Table of n, a(n) for n = 1..1192, a(n)<50000.
Programs
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Mathematica
Do[If[Prime[n]==2Prime[n+2]-Prime[n+3],Print[n]],{n,1,50000}] -
Scheme
;; With Antti Karttunen's IntSeq-library. (define A138042 (MATCHING-POS 1 1 (lambda (n) (= 2 (/ (+ (A000040 n) (A000040 (+ n 3))) (A000040 (+ n 2)))))))
Formula
a(n) = A066495(n) - 2.
Extensions
Formula corrected by Antti Karttunen, Jul 13 2013
Comments