This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A033157 Begins with (1, 4); avoids 3-term arithmetic progressions. 12
 1, 4, 5, 8, 10, 13, 14, 17, 28, 31, 32, 35, 37, 40, 41, 44, 82, 85, 86, 89, 91, 94, 95, 98, 109, 112, 113, 116, 118, 121, 122, 125, 244, 247, 248, 251, 253, 256, 257, 260, 271, 274, 275, 278, 280, 283, 284, 287, 325, 328, 329, 332, 334, 337, 338, 341, 352, 355, 356, 359, 361 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Also called Stanley Sequence S[1,4]. - Ralf Stephan, Jan 31 2014 REFERENCES F. Iacobescu, 'Smarandache Partition Type and Other Sequences.' Bull. Pure Appl. Sci. 16E, 237-240, 1997. H. Ibstedt, A Few Smarandache Sequences, Smarandache Notions Journal, Vol. 8, No. 1-2-3, 1997, 170-183. LINKS Eric Weisstein's World of Mathematics, Nonarithmetic Progression Sequence FORMULA Partial sums of Da(n), where Da(n) is defined in the PARI program. a(n) = A004793(n) + [n is even] + [ceiling(n/2) is even]. Proof by Lawrence Sze. - Ralf Stephan, Nov 15 2004 a(n) = A033161(n) - 1 = A185256(n) + 1. - Ralf Stephan, Jan 31 2014 PROG (PARI) Da(n)=if(n<1, 1, if(n%2==0, 3*Da(n/2)+5-13*((n/2)%2)-6*((n/2)%4==2), 3)) /* Ralf Stephan */ CROSSREFS Cf. A092482, A004793. Row 2 of array in A093682. Sequence in context: A304108 A214026 A174396 * A310574 A059659 A140459 Adjacent sequences:  A033154 A033155 A033156 * A033158 A033159 A033160 KEYWORD nonn,easy AUTHOR STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 15 00:00 EDT 2019. Contains 328025 sequences. (Running on oeis4.)