The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A248644

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Showing entries 1-10 | older changes

A248644

Evil numbers (A001969) remaining evil if any digit is deleted (zeros allowed).
(history; published version)

#21 by Alois P. Heinz at Sat Mar 14 15:52:52 EDT 2020

STATUS

proposed

approved

#20 by F. Chapoton at Sat Mar 14 14:18:27 EDT 2020

STATUS

editing

proposed

#19 by F. Chapoton at Sat Mar 14 14:18:19 EDT 2020

PROG

.... if n==0:

........ return trueTrue

.... else:

........ return sum(Integer(n).digits(base=2))%2==0

.... if not(is_evil(n)):

........ return falseFalse

.... else:

........ L=Integer(n).digits(base=10)

........ M=[]

........ for i in [0..len(L)-1]:

............ G=L[0:i]+L[i+1:]

............ M.append(is_evil(sum(G[i]*10^i for i in [0..len(G)-1])))

........ return sum(M)==len(M)

STATUS

approved

editing

Discussion

Sat Mar 14

14:18

F. Chapoton: use space to indent sage code

#18 by N. J. A. Sloane at Sat Oct 25 22:52:48 EDT 2014

STATUS

proposed

approved

#17 by Jon E. Schoenfield at Fri Oct 24 01:45:34 EDT 2014

STATUS

editing

proposed

#16 by Jon E. Schoenfield at Fri Oct 24 01:45:32 EDT 2014

COMMENTS

Although for numbers >9 we never put 0 instead of the removed digit, we include single-digit numbers 0,3,5,6,9 since, e.g., 3=03, etc.

single-digit numbers 0,3,5,6,9 since, e.g., 3=03, etc.

STATUS

proposed

editing

#15 by Vladimir Shevelev at Sun Oct 12 12:21:10 EDT 2014

STATUS

editing

proposed

#14 by Vladimir Shevelev at Sun Oct 12 12:19:35 EDT 2014

DATA

0, 3, 5, 6, 9, 30, 33, 36, 39, 53, 60, 63, 65, 66, 90, 95, 96, 99, 105, 120, 172, 175, 177, 178, 180, 209, 240, 243, 277, 300, 303, 306, 330, 340, 343, 360, 363, 366, 390, 396, 399, 430, 480, 483, 485, 486, 533, 534, 543, 571, 600, 603, 605, 606, 630, 633, 636, 658, 660, 663

OFFSET

1,12

COMMENTS

Although for numbers >9 we never put 0 instead of the removed digit, we include

single-digit numbers 0,3,5,6,9 since, e.g., 3=03, etc.

STATUS

proposed

editing

Discussion

Sun Oct 12

12:21

Vladimir Shevelev: OK, I include them.

#13 by Vladimir Shevelev at Sat Oct 11 05:33:35 EDT 2014

STATUS

editing

proposed

Discussion

Sat Oct 11

16:14

Tom Edgar: That one is maybe not the best because 0 is not prime. How about this one: A023110.

Sun Oct 12

12:00

M. F. Hasler: I'm in favour of prefixing the 5 single digit terms, maybe with a comment that explains that these are conventional. This improves search results for this sequence.

#12 by Vladimir Shevelev at Sat Oct 11 05:33:22 EDT 2014

CROSSREFS

Cf. A001969, A248478, A248642, A248659.

STATUS

proposed

editing