A138850 Weird numbers (A006037) not divisible by 5.

836, 7192, 7912, 9272, 10792, 17272, 45356, 73616, 83312, 91388, 113072, 222952, 243892, 254012, 338572, 343876, 351956, 388076, 407132, 410476, 465652, 470668, 475684, 477356, 482372, 490732, 495748, 500764, 502436, 507452, 512468, 515812

Offset

1,1

Comments

Up to 200000, there are only 11 weird numbers not divisible by 5.

Since no A006037(k) < 10^17 is odd, at least up to there, "divisible by 5" is equivalent to "ending in 0" (in base 10).

It appears that 4*11*19*p is an element of this sequence for p=1 and all primes p>547. Moreover, these seem to comprise most of the terms of this sequence.

Up to n=500, the only indices for which a(n) is not of this form are n=2,...,16, 18, 34, 38, 43, 64, 83, 148, 158, 236, 266, 296, 310.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..500 from M. F. Hasler)

Prog

(PARI) t=0; A138850=vector(50, i, until( (t+=2)%5 && is_A006037(t), ); t) \\ [Updated by M. F. Hasler, Jan 07 2014]

Crossrefs

Cf. A006037, A100696.

Sequence in context: A245947 A235288 A162945 * A357326 A322524 A016113

Adjacent sequences: A138847 A138848 A138849 * A138851 A138852 A138853

Keyword

nonn

Author

M. F. Hasler, Apr 02 2008

Status

approved