This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A301628 Numbers not divisible by 2, 3 or 5 (A007775) with digital root 7. 1
 7, 43, 61, 79, 97, 133, 151, 169, 187, 223, 241, 259, 277, 313, 331, 349, 367, 403, 421, 439, 457, 493, 511, 529, 547, 583, 601, 619, 637, 673, 691, 709, 727, 763, 781, 799, 817, 853, 871, 889, 907, 943, 961, 979, 997, 1033, 1051, 1069, 1087, 1123 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numbers == {7, 43, 61, 79} mod 90 with additive sum sequence 7{+36+18+18+18} {repeat ...}. Includes all prime numbers > 5 with digital root 7. LINKS Colin Barker, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (1,0,0,1,-1). FORMULA Numbers == {7, 43, 61, 79} mod 90. From Colin Barker, Sep 21 2019: (Start) G.f.: x*(7 + 36*x + 18*x^2 + 18*x^3 + 11*x^4) / ((1 - x)^2*(1 + x)*(1 + x^2)). a(n) = a(n-1) + a(n-4) - a(n-5) for n>5. (End) EXAMPLE 7+36=43; 43+18=61; 61+18=79; 79+18=97; 97+36=133. PROG (GAP) Filtered(Filtered([1..1200], n->n mod 2 <> 0 and n mod 3 <> 0 and n mod 5 <> 0), i->i-9*Int((i-1)/9)=7); # Muniru A Asiru, Apr 22 2018 (PARI) Vec(x*(7 + 36*x + 18*x^2 + 18*x^3 + 11*x^4) / ((1 - x)^2*(1 + x)*(1 + x^2)) + O(x^40)) \\ Colin Barker, Sep 21 2019 CROSSREFS Intersection of A007775 and A017245. Sequence in context: A062336 A085704 A243459 * A061241 A062337 A176252 Adjacent sequences:  A301625 A301626 A301627 * A301629 A301630 A301631 KEYWORD nonn,base,easy AUTHOR Gary Croft, Mar 24 2018 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 December 10 20:38 EST 2019. Contains 329909 sequences. (Running on oeis4.)